Bug fix: HDFFV-8933

Description:
Mac has changed to use the clang/clang++ compilers but compiler settings for production, debug and profile
were not setup.

Solution:
Setup default values for PROD_CFLAGS, PROD_CPPFLAGS, DEBUG_CFLAGS, DEBUG_CPPFLAGS.
PROFILE_CFLAGS and PROFILE_CPPFLAGS were set too but clang does not -pg or such for
profiling. Need to fix it later.

Tested: duck, swallow, and quail using --enable-production.


git-svn-id: https://svn.hdfgroup.uiuc.edu/hdf5/trunk@25654 dab4d1a6-ed17-0410-a064-d1ae371a2980