If building for 32 bit x86 target pass -march=i686 option to enable
atomic instructions.  i686 is usually the default arch but sometimes an
older one is selected (depends on gcc compile time configuration).

External unwind code doesn't exists for non-x86 platforms.
Allow LuaJIT to be compiled somehow.

A 'tentative definition' in C language is a global variable definition
missing both a storage class and an initializer, ex: int foo.
Traditionally it get's translated into a common symbol, allowing for
multiple definitions in different translation units to coexist.

Normally multiple definitions aren't allowed; unless they are common
symbols.  In the later case a linker picks one arbitrarily.

-fno-common alters tentative definitions translation, resulting in
a more strict and conformant semantics, multiple definitions are no
longer allowed.

This change was motivated by the OSX linker not handling common symbols
in static libraries
(https://stackoverflow.com/questions/19398742/os-x-linker-unable-to-find-symbols-from-a-c-file-which-only-contains-variables)

Enable monotonic timers (if available).

Enable floor() usage in computations (instead of a crude approximation
with bithacks).

Enable eventfd and signalfd usage on Linux.

Note: it was incomplete, made thing unnecessary complex and it did not
align with the CMake way (c) for crosscompilation.

Pass sysroot on OSX.
Make the code in luajit.cmake a bit more sane and straightforward.

Note: v1 of this patch was reverted due to performance regression.

This reverts commit 615f0985.

This reverts commit 3010b98b.

Pass sysroot.
Abort build if preprocessing fails (a stage in tarantool.h generation).

Note: it was incomplete, made thing unnecessary complex and it did not
align with the CMake way (c) for crosscompilation.

Pass sysroot on OSX.
Make the code in luajit.cmake a bit more sane and straightforward.

We were passing -g flag twice, just uncool.

Luajit comes with a custome buildsystem. Fixed passing custom
CC; it bites on FreeBSD since we are currently unable to build
with default CC (gh-786).

Issue was due to _Thread_local keyword used in the system
header which gcc4.8 fails to understand in c11 mode.
In --std=gnu99 mode it works.

Updated cmake test to claim no c11 support if ctype.h fails
to compile.

The origin was that 'vmdef.lua' was generated in
'${CMAKE_BINARY_DIR}/third_party/luajit/jit/', but was searched in
'${CMAKE_SOURCE_DIR}/...'.
ALSO: when we start to generate *.c files from luajit's libraries we made
statement, that we don't built with OS pre-built luajits.

Introduce a layer of wrappers for a number of internal box functions,
dealing with accss to spaces and indexes.

These wrappers:
    * don't throw exceptions
    * have a common prefix box_
    * are exported in the server development headers

Rewrite Lua C bindings to use the public API described above.
Rewrite Lua FFI bindings to do the same.
Add test.

cmake 2.8.9 doesn't have CMAKE_CXX_COMPILER_VERSION

Fixes gh-849 'Compile error on CentOS'

Expliclitly prohibit Gcc versions which do not support lambdas.

Implement basic support for stored functions in C/C++.

- split away struct func from struct func_def (function
object and function definition object).
- extend box.schema.func.create() to accept 'language' argument.
- move module API related cmake magic to its own file
- add test/lib to gitignore
- update to the new test-run
- add a test

 - mysql moved to https://github.com/tarantool/mysql
 - pg moved to https://github.com/tarantool/pg

Please consult documentation on GitHub for more details.

This patch adds `src/module.h` header file with definition of all public
API functions suitable to use in Lua/C modules for Tarantool. This header
is automatically generated from src/*.h by CMake (`make generate_module_api`)
by extracting code blocks between /** \cond public */ /* \endcond public */
Doxygen-style comments.

Definitions of functions in module.h are frozen and must not be changed by
future commits/releases. A new test case `app/module_api` is added to check
compilation, linkage and loading of Lua modules and functionality of
provided API functions.

Other changes:

 * Convert mysql and pg to use module.h and prepare to convert to .c
 * Fix includes in say.h, coeio.h
 * Rename luaL_pushnumber64 to luaL_pushuint64 and
          luaL_pushinumber64 to luaL_pushint64
 * Add LUA_API macros to public luaL_* functions (actually adds extern "C")

* Added define HAVE_GNU_READLINE and check it for detecting non GNU readline library