Refactored static build process to use static-build/CMakeLists.txt
instead of Dockerfile.staticbuild (this allows to support static
build on macOS). Following third-party dependencies for static build
are installed via cmake `ExternalProject_Add`:
  - OpenSSL
  - Zlib
  - Ncurses
  - Readline
  - Unwind
  - ICU

* Added support static build for macOS
* Fixed `CONFIGURE_COMMAND` while building bundled libcurl for static
  build at file cmake/BuildLibCURL.cmake:
    - disable building shared libcurl libraries (by setting
      `--disable-shared` option)
    - disable hiding libcurl symbols (by setting
      `--disable-symbol-hiding` option)
    - prevent linking libcurl with system libz (by setting
      `--with-zlib=${FOUND_ZLIB_ROOT_DIR}` option)
* Removed Dockerfile.staticbuild
* Added new gitlab.ci jobs to test new style static build:
  - static_build_cmake_linux
  - static_build_cmake_osx_15
* Removed static_docker_build gitlab.ci job

Closes #5095

Co-authored-by: Yaroslav Dynnikov <yaroslav.dynnikov@gmail.com>

Tarantool has LTO support, however while building luajit this opt. was
omitted. Patch adds necessary flag to turn it on.

Closes #3743

Clang undefined behaviour sanitizer was turned on using
-fsanitize=undefined flag, which is supposed to turn on all the
sanitizations, except a few ones. Not needed sanitations were
turned off explicitly, using -fno-sanitize=<type> flags. However
appeared it does not work with some flags. For example,
nullability sanitations can't be turned off when
-fsanitize=undefined is used.

Nullability sanitations lead to lots of false-positive fails
such as typeof(*obj) where obj is NULL, or memcpy() with NULL
destination but 0 size.

The patch splits -fsanitize=undefined into separate flags and
never turns on nullability checks.

Part of #4609

Fixed static build with '-DBUILD_STATIC=ON' option:

* Added cmake option CMAKE_DL_LIBS to icu library for
  test/unit tests binaries builds at file:
    cmake/FindICU.cmake
  due to fail:
    [ 84%] Linking CXX executable vy_point_lookup.test
    /usr/local/lib/libicuuc.a(putil.ao): In function `uprv_dl_open_62':
    putil.cpp:(.text+0x1a22): undefined reference to `dlopen'
    /usr/local/lib/libicuuc.a(putil.ao): In function `uprv_dlsym_func_62':
    putil.cpp:(.text+0x1a7d): undefined reference to `dlsym'
    /usr/local/lib/libicuuc.a(putil.ao): In function `uprv_dl_close_62':
    putil.cpp:(.text+0x1a61): undefined reference to `dlclose'
    collect2: error: ld returned 1 exit status

* Added cmake option CMAKE_DL_LIBS to gomp library for
  test/unit tests binaries builds at file:
    cmake/BuildMisc.cmake
  due to fail:
    [ 91%] Linking CXX executable bps_tree.test
    /usr/lib/gcc/x86_64-linux-gnu/7/libgomp.a(target.o): In function `gomp_target_init':
    (.text+0x8b): undefined reference to `dlopen'
    (.text+0xa2): undefined reference to `dlsym'
    (.text+0xd9): undefined reference to `dlclose'
    (.text+0x29b): undefined reference to `dlsym'
    (.text+0x2a8): undefined reference to `dlerror'
    (.text+0x2d0): undefined reference to `dlsym'
    (.text+0x2e9): undefined reference to `dlsym'
    (.text+0x300): undefined reference to `dlsym'
    (.text+0x317): undefined reference to `dlsym'
    (.text+0x330): undefined reference to `dlsym'
    /usr/lib/gcc/x86_64-linux-gnu/7/libgomp.a(target.o):(.text+0x34d): more undefined references to `dlsym' follow
    /usr/lib/gcc/x86_64-linux-gnu/7/libgomp.a(target.o): In function `gomp_target_init':
    (.text+0x9cc): undefined reference to `dlerror'
    collect2: error: ld returned 1 exit status

Close #5024

Option ENABLE_UB_SANITIZER enables clang undefined behaviour
sanitizer. So far the only UB to detect was alignment violation.
This was the biggest problem found by the sanitizer. Now when it
is fixed, most of the other types of UB are also turned on to fix
them as well.

There is a few of exceptions - pointer type overflow, vptr check,
and all types of integer overflow and truncation.

Pointer type overflow detection is disabled because it is abused
in the source code a lot, by stailq data structure.

Vptr sanitation is a runtime check ensuring that a pointer at a
non-POD type really points at an object of this type, using RTTI.
The check false-positively fails in alter.cc when AlterSpaceOp
class objects are stored in an rlist, and the list is iterated
using rlist_foreach_entry(). In the cycle there is a condition:

    &item->member != head

In the end the 'item' points not at an AlterSpaceOp, but at the
rlist head - offsetof(typeof(item), member), at an rlist
structure. Despite 'item' is never dereferenced, clang anyway
generates vptr check here, which of course fails. Note,
'&item->member' does not dereference item. It is
item + offsetof(typeof(item), member). Just another address a few
bytes after item.

Integer overflow and truncation are disabled because SQL uses
int64_t variables as a container of values of range [INT64_MIN,
UINT64_MAX]. This works because there is a flag 'is_neg' near
each such value which tells how to interpret it - as negative
int64_t, or as positive uint64_t. As a result, some operations
lead to a false-positive overflow. For example, consider
expr_code_int() function. It essentially can do this:

    int64_t value;
    ((uint64_t *)&value) = 9223372036854775808;
    value = -value;

9223372036854775808 is -INT64_MIN. It can't be stored in int64_t.
But the thing is that (uint64_t)9223372036854775808 is stored
exactly like (int64_t)INT64_MIN, in binary form. So the expression
"value = -value" looks perfectly valid:
"value = -9223372036854775808", But in fact it is interpreted as
"value = -(-9223372036854775808)".

These integer overflow/truncation problems are going to be fixed
in a separate commit due to big amount of changes needed for that.

Part of #4609

Clang has a built-in sanitizer for undefined behaviour. Such as
wrong memory alignment, array boundaries violation, 0 division,
bool values with non standard content, etc.

The sanitizer emits runtime checks which lead to either crash, or
a trap, or a warning print, depending on what is chosen.

The patch makes it possible to turn the sanitizer on and catch
UBs. The only supported UB so far is alignment check. Other types
can be added gradually, along with fixing bugs which they find.

The UB sanitizer is activated for ASAN builds in CI.

Part of #4609

Warning about invalid offsetof() (used on non-POD types) was set
for g++, but wasn't for clang++.

Warning about invalid alignof() (when expression is passed to it
instead of a type) wasn't ignored, but is going to be very
useful in upcoming unaligned memory access patches. That allows
to write something like:

    struct some_long_type *object = region_aligned_alloc(
            region, size, alignof(*object));

This will work even if type of 'object' will change in future,
and so it is safer. And shorter.

Part of #4609

OpenBSD includes DL library in a base system

Part of #4967

Part of #4967

Part of #4967

Fixed static build with '-DBUILD_STATIC=ON' option:

 - installed liblzma-dev library for libunwind static, due to found that
   static libunwind library uses undefined lzma functions:
     nm -a /usr/lib/x86_64-linux-gnu/libunwind-x86_64.a | grep lzma
                 U lzma_index_buffer_decode
                 U lzma_index_end
                 U lzma_index_size
                 U lzma_index_uncompressed_size
                 U lzma_stream_buffer_decode
                 U lzma_stream_footer_decode
   while dynamic libunwind correctly sees liblzma installed:
     ldd /usr/lib/x86_64-linux-gnu/libunwind-x86_64.so | grep lzma
       liblzma.so.5 => /lib/x86_64-linux-gnu/liblzma.so.5 (0x00007f8fd1c23000)
   so to fix it the static library of lzma was needed.

 - added lzma library to unwind library for Tarantool build at file:
     cmake/compiler.cmake
   due to fail:
     /usr/lib/x86_64-linux-gnu/libunwind-x86_64.a(elf64.o):
       In function `xz_uncompressed_size':
     ./src/elfxx.c:194: undefined reference to `lzma_stream_footer_decode'
     ./src/elfxx.c:201: undefined reference to `lzma_index_buffer_decode'
     ./src/elfxx.c:205: undefined reference to `lzma_index_size'
     ./src/elfxx.c:210: undefined reference to `lzma_index_end'
     ./src/elfxx.c:207: undefined reference to `lzma_index_uncompressed_size'
     ./src/elfxx.c:210: undefined reference to `lzma_index_end'
     /usr/lib/x86_64-linux-gnu/libunwind-x86_64.a(elf64.o):
       In function `_Uelf64_extract_minidebuginfo':
     ./src/elfxx.c:278: undefined reference to `lzma_stream_buffer_decode'
     collect2: error: ld returned 1 exit status
     test/unit/CMakeFiles/luaL_iterator.test.dir/build.make:134:
       recipe for target 'test/unit/luaL_iterator.test' failed
     make[2]: *** [test/unit/luaL_iterator.test] Error 1

 - added dl library to gomp library for test/unit tests
   binaries builds at file:
     cmake/BuildMisc.cmake
   due to fail:
     /usr/lib/gcc/x86_64-linux-gnu/7/libgomp.a(target.o):(.text+0x34d):
       more undefined references to `dlsym' follow
     /usr/lib/gcc/x86_64-linux-gnu/7/libgomp.a(target.o): In function
       `gomp_target_init':
     (.text+0x9cc): undefined reference to `dlerror'
     collect2: error: ld returned 1 exit status

  - added dl library to icu library for test/unit tests
   binaries builds at file:
     cmake/FindICU.cmake
   due to fail:
     /usr/x86_64-linux-gnu/libicuuc.a(putil.ao):
       In function `uprv_dl_open_60':
     (.text+0x1ce2): undefined reference to `dlopen'
     /usr/x86_64-linux-gnu/libicuuc.a(putil.ao):
       In function `uprv_dlsym_func_60':
     (.text+0x1d3d): undefined reference to `dlsym'
     /usr/x86_64-linux-gnu/libicuuc.a(putil.ao):
       In function `uprv_dl_close_60':
     (.text+0x1d21): undefined reference to `dlclose'
     collect2: error: ld returned 1 exit status

Added static build to gitlab-ci in release check criteria named
as static_build job. Previously named static_build job renamed to
static_docker_build, due to it checks the build at Dockerfile.

Also moved static build make targets from .gitlab.mk to .travis.mk
to store it in common place with the other test/build make targets.
Moved environement from .gitlab-ci.yml file into make targets to
make this targets true building in static w/o additional setup.

Close #4551

The change enables memory leaks detection to existing ASAN testing
routine and introduces suppression files with the corresponding
exception list:
 * address sanitizer for compile-time: asan/asan.supp
 * memory leak sanitizer for run-time: asan/lsan.supp

Furthermore, added engine and replication suites for ASAN testing
routine.

Additionally to the tests blacklisted within #4359,
'box/on_shutdown.test.lua' is also disabled since it fails the
introduced leak check. All blacklisted tests have to be enabled
within #4360.

Close #2058

SO_LINGER makes no much sense for unix-sockets, and Microsoft WSL
is returning EINVAL if setsockopts called for SO_LINGER over unix
sockets:

  [004] 2020-03-11 18:42:29.592 [29182] main/102/app sio.c:169 !> SystemError setsockopt(SO_LINGER), called on fd 16, aka
  [004] 2020-03-11 18:42:29.592 [29182] main/102/app F> can't initialize storage: setsockopt(SO_LINGER), called on fd 16,
  [004] 2020-03-11 18:42:29.592 [29182] main/102/app F> can't initialize storage: setsockopt(SO_LINGER), called on fd 16,

And it's sort of correct here, but the problem is Linux is simply
silently ignoring it, which passes tests.

After much debates we decided to work-around this case via CMAKE
define.

NB! In a future (April/May 2020), when WSL2 with full Linux kernel
would be released we should disable this check.

Acked-by: Cyrill Gorcunov <gorcunov@gmail.com>

Since this build flag has been removed as a result of reverting the
tarantool/luajit@d4e985a, its definition in the corresponding Tarantool
cmake file is irrelevant.

Furthermore, considering the breakage faced in #4770 the following tests
are introduced:
* the check whether space __pairs metamethod is set to space.pairs to
  create a Lua Fun iterator that handles __pairs manually underneath.
* the check whether pairs builtin behaviour doesn't change when __pairs
  is set e.g. on space object.

Follow-up #4560
Closes #4770

Reviewed-by: Vladislav Shpilevoy <v.shpilevoy@tarantool.org>
Signed-off-by: Igor Munkin <imun@tarantool.org>

libcurl has a built-in threaded resolver used for asynchronous DNS
requests, however, when DNS server is slow to respond, the request still
hangs tarantool until it is finished. The reason is that curl calls
thread_join on the resolving thread internally upon timeout, making the
calling thread hang until resolution has ended.
Use c-ares as an asynchronous resolver instead to eliminate the problem.

Closes #4591

Turns on LUAJIT_ENABLE_PAIRSMM flag for tarantool build.
Now __pairs/__ipairs metamethods are available.

Closes #4650

After ea5929db ('build: fix OpenSSL
linking problems on FreeBSD') we set CFLAGS explicitly (possibly to an
empty value) when invoking a configure script for curl. When this
parameter is set the script does not use a value of environment variable
CFLAGS.

Before this commit LDFLAGS environment variable can affect build of curl
submodule. This can lead to a problem when a user or a tool set CFLAGS
and LDFLAGS both and some linker flag assumes that some compilation flag
is present. Here we set empty LDFLAGS explicitly to avoid using of the
environment variable.

A distributive build tool such as rpmbuild or emerge usually sets CFLAGS
and LDFLAGS. The problem with incompatible compiler / linker options has
been reveal under rpmbuild on CentOS 8 with hardened build enabled
(which is so when backtraces are disabled).

It is not clear whether we should follow environment variables or values
determined by CMake for CFLAGS, CPPFLAGS and LDFLAGS when building a
submodule (such as luajit and curl). Let's decide about this later.

Part of #4543.

Reviewed-by: Alexander V. Tikhonov <avtikhon@tarantool.org>
Reviewed-by: Igor Munkin <imun@tarantool.org>

This allows to overcome problems when CMake chooses one toolchain to
build tarantool, but a library (libluajit.a or libcurl.a) is built using
another (incompatible) toolchain.

Fixes #4587.

FreeBSD has OpenSSL as part of the base system: libraries are located in
/usr/lib, headers are in /usr/include. However a user may install the
library into /usr/local/{lib,include} from ports / pkg. In this case
tarantool did choose /usr/local version, while libcurl will pick up a
base system library. This is fixed by passing --with-ssl option with an
argument (/usr/local or /usr if custom -DOPENSSL_ROOT_DIR=<...> is not
passed).

Now the behaviour is the following. If -DOPENSSL_ROOT_DIR=<...> is
passed, then try to use OpenSSL from it. Otherwise find the library in
/usr/local and then in /usr. This is right as for tarantool's crypto
module as well as for libcurl submodule.

There is a flaw here: a user is unable to choose a base system library
if a ports / pkg version of OpenSSL is installed. The reason here is
that tarantool's crypto module depends on other libraries and
-I/usr/local/include may be added to build options. I have no good
solution for that, so `cmake . -DOPENSSL_ROOT_DIR=/usr` will give a
warning on FreeBSD and `gmake` likely will fail if libraries are of
different versions (see cmake/os.cmake comments for more information).
See also a [discussion][1] in FreeBSD community about all those /usr and
/usr/local problems.

There were two other problems that may fail tarantool build on FreeBSD:
they are fixed in this commit and described below.

First, libcurl's configure script chooses GCC by default if it exists
(say, installed from ports / pkg). It is unexpected behaviour when
tarantool sources itself are built with clang. Now it is fixed by
passing a compiler explicitly to the libcurl's configure script: the
library will use base system clang by default or one that a user pass to
tarantool's cmake.

Side note: GCC has /usr/local/include in its default headers search
paths; libcurl's configure script chooses GCC as a compiler and OpenSSL
from a base system by default (when CC and --with-ssl=<...> are not set)
that leads to OpenSSL header / library mismatch. It is the primary
reason of the build fail that was fixed in
1f2338bd ('build: FreeBSD packages
installation'). It is not much relevant anymore, because we don't try to
link with a base system OpenSSL if /usr/local one exists (however if it
is asked explicitly with -DOPENSSL_ROOT_DIR=<...> we'll do, but will
give a warning). Anyway, it is important to know such details if we'll
change build scripts in a future.

Second, backtraces are not supported on FreeBSD, but were enabled if
libunwind headers is found. This leads to an error on cmake stage,
because of inability to find a right library (this is a bug). Now we
disable backtraces on FreeBSD by default even if libunwind is found. See

When CC is passed to libcurl's configure script, the new problem opens
on Mac OS. CMake chooses XCode toolchain by default (at least on a
particular system where I tried it), which requires -isysroot=<SDK_PATH>
option to be passed to a preprocessor and a compiler in order to find
system headers. See [2] for more information.

[1]: https://wiki.freebsd.org/WarnerLosh/UsrLocal
[2]: https://developer.apple.com/documentation/xcode_release_notes/xcode_10_release_notes#3035623

Follows up #4490.

System-wide dynamic libraries usually (always?) have NEEDED and RUNPATH
tags in a dynamic section (as `readelf -d /usr/lib/lib<...>.so` shows),
so when we link, say, with libssl.so, which depends on libz.so, a linker
does not complain against unresolved symbols that can be found in Z
library (if it is installed within a system).

Things are different when we linking with a static library. Say, when we
linking with libssl.a, which contains an unresolved symbol from Z
library, a linker reports an error. It is not possible to store an
information where to find unresolved symbols (NEEDED / RUNPATH) in a
static library (AFAIK).

We depend on three libraries that are depend on Z library: libcurl,
libssl and libcrypto (two latter are part of OpenSSL). When one of those
libraries is linked statically we should link with libz.so or libz.a
(depending on BUILD_STATIC flag). The patch doing exactly this.

The patch changes OPENSSL_LIBRARIES variable to fix the issue with
static linking of OpenSSL libraries. It also changes CURL_LIBRARIES in
the same way, however this does not alter any visible behaviour, because
OPENSSL_LIBRARIES is added to CURL_LIBRARIES. The latter change was made
to unify the way to choose libraries to link with: it is pure
refactoring part.

Fixes #4437.

Hold libcurl-7.65.3. This version is not affected by the following
issues:

* #4180 ('httpc: redirects are broken with libcurl-7.30 and older');
* #4389 ('libcurl memory leak');
* #4397 ('HTTPS seem to be unstable').

After this patch libcurl will be statically linked when
ENABLE_BUNDLED_LIBCURL option is set. This option is set by default.

Closes #4318

@TarantoolBot document
Title: Tarantool dependency list was changed

* Added build dependencies: autoconf, automake, libtool, zlib-devel
  (zlib1g-dev on Debian).
* Added runtime dependencies: zlib (zlib1g on Debian).
* Removed build dependencies: libcurl-devel (libcurl4-openssl-dev on
  Debian).
* Removed runtime dependencies: curl.

The reason is that now we use compiled-in libcurl: so we don't depend on
a system libcurl, but inherit its dependencies.

Add fixed-point decimal type to tarantool core.
Adapt decNumber floating-point decimal library for the purpose, write a
small wrapper and add unit tests.

A new decimal type is an alias for decNumber numbers from the decNumber
library.
Arithmetic operations (+, -, *, /) and some mathematic functions
(ln, log10, exp, pow, sqrt) are available together with methods to
pack and unpack decimal to and from its packed representation (useful
for serialization).

We introduce a single context for all the arithmetic operations
on decimals, which enforces both number precision and scale to be
in range [0, 38]. NaNs and Infinities are restricted.

Part of #692

Added to cmake environment CMAKE_DL_LIBS (The name of the library
that has dlopen and dlclose in it, usually -ldl) to openssl build
to add DL library, to fix the following fails:

Linking CXX executable crypto.test
/usr/local/lib64/libcrypto.a(dso_dlfcn.o): In function `dlfcn_globallookup':
dso_dlfcn.c:(.text+0x11): undefined reference to `dlopen'
dso_dlfcn.c:(.text+0x24): undefined reference to `dlsym'
dso_dlfcn.c:(.text+0x2f): undefined reference to `dlclose'
/usr/local/lib64/libcrypto.a(dso_dlfcn.o): In function `dlfcn_bind_func':
dso_dlfcn.c:(.text+0x334): undefined reference to `dlsym'
dso_dlfcn.c:(.text+0x3f2): undefined reference to `dlerror'
/usr/local/lib64/libcrypto.a(dso_dlfcn.o): In function `dlfcn_load':
dso_dlfcn.c:(.text+0x459): undefined reference to `dlopen'
dso_dlfcn.c:(.text+0x4c9): undefined reference to `dlclose'
dso_dlfcn.c:(.text+0x502): undefined reference to `dlerror'
/usr/local/lib64/libcrypto.a(dso_dlfcn.o): In function `dlfcn_pathbyaddr':
dso_dlfcn.c:(.text+0x5a1): undefined reference to `dladdr'
dso_dlfcn.c:(.text+0x601): undefined reference to `dlerror'
/usr/local/lib64/libcrypto.a(dso_dlfcn.o): In function `dlfcn_unload':
dso_dlfcn.c:(.text+0x662): undefined reference to `dlclose'
collect2: error: ld returned 1 exit status
make[2]: *** [test/unit/crypto.test] Error 1
make[1]: *** [test/unit/CMakeFiles/crypto.test.dir/all] Error 2

Closes #4245

It is important to have testing jobs that build the project with both
-Werror and -O2 to keep the code clean. -O2 is needed, because some
compiler warnings are available only after extra analyzing passes that
are disabled with lesser optimization levels.

The first attempt to add -Werror for release testing jobs was made in
da505ee7 ('Add -Werror for CI (1.10
part)'), but it mistakely doesn't enable -O2 for RelWithDebInfoWError
build. It is possible to fix it in this way:

 | --- a/cmake/compiler.cmake
 | +++ b/cmake/compiler.cmake
 | @@ -113,10 +113,14 @@ set (CMAKE_C_FLAGS_DEBUG
 |      "${CMAKE_C_FLAGS_DEBUG} ${CC_DEBUG_OPT} -O0")
 |  set (CMAKE_C_FLAGS_RELWITHDEBINFO
 |      "${CMAKE_C_FLAGS_RELWITHDEBINFO} ${CC_DEBUG_OPT} -O2")
 | +set (CMAKE_C_FLAGS_RELWITHDEBINFOWERROR
 | +    "${CMAKE_C_FLAGS_RELWITHDEBINFOWERROR} ${CC_DEBUG_OPT} -O2")
 |  set (CMAKE_CXX_FLAGS_DEBUG
 |      "${CMAKE_CXX_FLAGS_DEBUG} ${CC_DEBUG_OPT} -O0")
 |  set (CMAKE_CXX_FLAGS_RELWITHDEBINFO
 |      "${CMAKE_CXX_FLAGS_RELWITHDEBINFO} ${CC_DEBUG_OPT} -O2")
 | +set (CMAKE_CXX_FLAGS_RELWITHDEBINFOWERROR
 | +    "${CMAKE_CXX_FLAGS_RELWITHDEBINFOWERROR} ${CC_DEBUG_OPT} -O2")
 |
 |  unset(CC_DEBUG_OPT)

However I think that a build type (and so `tarantool --version`) should
not show whether -Werror was passed or not. So I have added
ENABLE_WERROR CMake option for that. It can be set like so:

 | cmake . -DCMAKE_BUILD_TYPE=RelWithDebInfo -DENABLE_WERROR=ON

Enabled the option in testing Travis-CI jobs with the RelWithDebInfo
build type. Deploy jobs don't include it as before.

Fixed all -Wmaybe-uninitialized and -Wunused-result warnings. A few
notes about the fixes:

* net.box does not validate received data in general, so I don't add a
  check for autoincrement IDs too. Set the ID to INT64_MIN, because this
  value is less probably will appear here in a normal case and so is the
  best one to signal a user that something probably going wrongly.
* xrow_decode_*() functions could read uninitialized data from
  row->body[0].iov_base in xrow_on_decode_err() when printing a hex code
  for a row. It could be possible when the received msgpack was empty
  (row->bodycnt == 0), but there were expected keys (key_map != 0).
* getcwd() is marked with __attribute__((__warn_unused_result__)) in
  glibc, but the buffer filled by this call is not used anywhere and so
  just removed.
* Vinyl -Wmaybe-uninitialized warnings are false positive ones.

Added comments and quotes into .travis.yml to ease reading. Removed
"test" word from the CentOS 6 job name, because we don't run tests on
this distro (disabled in the RPM spec).

Fixes #4178.

Fixed Mojave Mac build with setting MACOSX_DEPLOYMENT_TARGET environment
variable for LuaJIT's Makefile. This variable specifies the minimum
version of OS X on which the target binaries are to be deployed.

The reason why we need to set MACOSX_DEPLOYMENT_TARGET to at least 10.6
is that 10.4 SDK (which is set by default in LuaJIT's Makefile) is not
longer included in Mac OS X Mojave 10.14.

See also https://github.com/LuaJIT/LuaJIT/issues/484

We already set -Wl,-macosx_version_min,10.6 (-macosx_version_min and
MACOSX_DEPLOYMENT_TARGET are synonymous), but it affects only a linker.
We possibly should remove -macosx_version_min, because it superseded by
MACOSX_DEPLOYMENT_TARGET, but it should be done with verification that
the original problem really fixed by the new way to set a deployment
target. This is not part of this patch.

Removed virtualenv usage in CI for OS X (so pip just installs packages
into a system), because OS X Mojave 10.14 does not offer virtualenv by
default.

Fixed #3797

The build time error is confusing for users. The patch makes the error
explicit and moves it to the cmake stage.

Follow up of #3070.

LLVM changes the API in the compiler-rt commit [1]. According to the
date of the commit it is between clang-3.9.0 and clang-3.9.1.

[1]: https://github.com/llvm-mirror/compiler-rt/commit/0b95585616bd28fc0b738289bcc5f7887d7c304e

Fixes #3070.

FreeBSD 10.4 has no libdl.so.

Fixes #3750.

Added -DENABLE_LTO=ON/OFF cmake option, OFF by default.

LTO speeds up cpu-intensive workloads by up to 20% (see [1] and [2]).

Requirements to enable LTO:

- cmake >= 3.9;
- Linux: ld.bfd / ld.gold from binutils >= 2.31 (or later 2.30)
  (gold >= 1.15);
- Mac OS: xcode >= 8 (earlier versions are not tested).

The requirement of the recent ld version is due to bug with exporting
symbols from dynamic list when LTO is enabled, see [3].

Note: -Wlto-type-mismatch on GCC (enabled by default with -flto) gives
namy warnings. Filed [4] to investigate it.

Note: LuaJIT will be compiled w/o LTO despite the option set, filed [5].

[1]: https://github.com/tarantool/tarantool/wiki/performance-research
[2]: https://gist.github.com/Khatskevich/31a2da6ab46ce903120e7a03d65966db
[3]: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=84901
[4]: https://github.com/tarantool/tarantool/issues/3742
[5]: https://github.com/tarantool/tarantool/issues/3743

Closes #3117

f

Added MAKE_BUILD_TYPE=RelWithDebInfoWError option, which means enabling
-DNDEBUG=1, -O2 and -Wall -Wextra -Werror. This ensures we have clean
release build without warnings.

Fixed found -Wunused-variable and -Wunused-parameter warnings.

Part of #3238.

The problem is that clang does not support -Wno-cast-function-type flag.
It is the regression from 8c538963.

Follow up of #3685.
Fixes #3701.

Since addition of -fopenmp to compiler also means
addition of -lgomp to the link stage, pass -fno-openmp
to the linking stage in case of static build. In that
case OMP functions are statically linked into libmisc.

Also, emit error if trying to perform static build using
clang.

A possibility to build tarantool with included library dependencies.
Use the flag -DBUILD_STATIC=ON to build statically against curl, readline,
ncurses, icu and z.
Use the flag -DOPENSSL_USE_STATIC_LIBS=ON to build with static
openssl

Changes:
  * Add FindOpenSSL.cmake because some distributions do not support the use of
  openssl static libraries.
  * Find libssl before curl because of build dependency.
  * Catch all bundled libraries API and export then it in case of static
  build.
  * Rename crc32 internal functions to avoid a name clash with linked libraries.

Notes:
  * Bundled libyaml is not properly exported, use the system one.
  * Dockerfile to build static with docker is included

Fixes #3445

Fixing build under FreeBSD:
Undefined symbol "iconv_open"
Add compile time build check with FindICONV.cmake
and a wrapper to import relevant symbol names with include file.

Closes #3441

No more `include/yaml.h` and `lib/libyaml_static.a` installs.

closes gh-3547

If curl does not have SSL support, don't panic, honor CURL_FIND_REQUIRED
variable, and panic only if it's set.

Correct the grammar in the error message.

On MAC several old curl versions don't support SSL by default.
Try to check it and print error message if so.

Close #3065