Add definition for M_PI

Reviewed by: Tom Stellard



git-svn-id: https://llvm.org/svn/llvm-project/libclc/trunk@209848 91177308-0d34-0410-b5e6-96231b3b80d8
Fix _F definitions

The 'f' was missing and, hence, the values were
considered to be doubles instead of floats.

Reviewed by: Tom Stellard



git-svn-id: https://llvm.org/svn/llvm-project/libclc/trunk@209849 91177308-0d34-0410-b5e6-96231b3b80d8
Add more log related float constants



git-svn-id: https://llvm.org/svn/llvm-project/libclc/trunk@209850 91177308-0d34-0410-b5e6-96231b3b80d8