create CPPFLAGS_STD and make both CFLAGS_STD and CPPFLAGS_STD avalaible for CFLAGS and CXXFLAGS
Merge pull request #233 from WeAreLeka/std-flags

Using CFLAGS_STD and CPPFLAGS_STD
Revert "Using CFLAGS_STD and CPPFLAGS_STD"
Merge pull request #235 from sudar/revert-233-std-flags

Revert "Using CFLAGS_STD and CPPFLAGS_STD"
add CFLAGS_STD and CXXFLAGS_STD defaults
Merge pull request #234 from WeAreLeka/std-flags

CFLAGS_STD and CXXFLAGS_STD