CMake: fix LUAJIT_USE_XXX definitions

LuaJIT has some configuration flags which can be switched via
-DLUAJIT_USE_OPTION defines, e.g. USE_ASAN or USE_VALGRIND.
Before this patch these definitions were added by CMake to XCFLAGS
variable and passed to LuaJIT's Makefile. However, some of these
flags also affect the content of lj_xxx.h internal header files,
which were included by Tarantool (see utils.c) and compiled WITHOUT
proper flags. This situation might lead to inconsistent ABI between
compiled libluajit.a and Tarantool.

This patch adds all LUAJIT_USE_XXX defines to CMake's COMPILE_FLAGS
in order to enable these flags globally, then parses COMPILE_FLAGS
and adds them to LuaJIT's XCFLAGS.

Needed for #2643

cmake/luajit.cmake

@@ -167,8 +167,8 @@ macro(luajit_build)
         else ()
             set (luajit_ccdebug -g)
         endif ()
-        set (luajit_xcflags ${luajit_xcflags}
-            -DLUA_USE_APICHECK -DLUA_USE_ASSERT)
+        add_definitions(-DLUA_USE_APICHECK=1)
+        add_definitions(-DLUA_USE_ASSERT=1)
     else ()
         set (luajit_ccopt -O2)
         set (luajit_ccdbebug "")
@@ -198,15 +198,21 @@ macro(luajit_build)
         set (luajit_ccdebug ${luajit_ccdebug} -fprofile-arcs -ftest-coverage)
     endif()
     if (ENABLE_VALGRIND)
+        add_definitions(-DLUAJIT_USE_SYSMALLOC=1)
+        add_definitions(-DLUAJIT_USE_VALGRIND=1)
         set (luajit_xcflags ${luajit_xcflags}
-            -DLUAJIT_USE_VALGRIND -DLUAJIT_USE_SYSMALLOC
             -I${PROJECT_SOURCE_DIR}/src/lib/small/third_party)
     endif()
     # AddressSanitizer - CFLAGS were set globaly
     if (ENABLE_ASAN)
-        set (luajit_xcflags ${luajit_xcflags} -DLUAJIT_USE_ASAN)
+        add_definitions(-DLUAJIT_USE_ASAN=1)
         set (luajit_ldflags ${luajit_ldflags} -fsanitize=address)
     endif()
+    # Add all COMPILE_DEFINITIONS to xcflags
+    get_property(defs DIRECTORY PROPERTY COMPILE_DEFINITIONS)
+    foreach(def ${defs})
+        set(luajit_xcflags ${luajit_xcflags} -D${def})
+    endforeach()
     set (luajit_buildoptions
         BUILDMODE=static
         HOST_CC="${luajit_hostcc}"