CMake : Do not add compile flags, such as -Wconversion with ADD_DEFINITIONS

This broke clang-cl, apparently when compiling version resource file with
RC tool, because RC would not aceept -Wxxx at all.

cmake/mysql_version.cmake

@@ -115,7 +115,7 @@ ENDIF()
 # Add version information to the exe and dll files
 # Refer to http://msdn.microsoft.com/en-us/library/aa381058(VS.85).aspx
 # for more info.
-IF(MSVC AND NOT CLANG_CL)
+IF(MSVC)
     # Tiny version is used to identify the build, it can be set with cmake -DTINY_VERSION=<number>
     # to bzr revno for example (in the CI builds)
     IF(NOT TINY_VERSION)

storage/innobase/innodb.cmake

@@ -119,7 +119,7 @@ ENDIF()
 
 IF (CMAKE_CXX_COMPILER_ID MATCHES "Clang" OR
     CMAKE_CXX_COMPILER_ID STREQUAL "GNU")
-  ADD_DEFINITIONS("-Wconversion -Wno-sign-conversion")
+  SET(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wconversion -Wno-sign-conversion")
   SET_SOURCE_FILES_PROPERTIES(fts/fts0pars.cc
     PROPERTIES COMPILE_FLAGS -Wno-conversion)
 ENDIF()