Bug#17959689: MAKE GCC AND CLANG GIVE CONSISTENT COMPILATION WARNINGS
Bug#18313717: ENABLE -WERROR IN MAINTANER MODE WHEN COMPILING WITH CLANG
Bug#18510941: REMOVE CMAKE WORKAROUNDS FOR OLDER VERSIONS OF OS X/XCODE
Backport from mysql-5.6 to mysql-5.5
option for specific compilers
Reorganize the maintainer mode cmake code to allow options
for specific compilers. For now, enable -Wcheck for ICC,
but do not turn warnings into errors.