Don't force compilers
Don't force compilers

Use GNU M4 macros to check and use the C99/C++11 compilers.

lianaduenha/ArchC,tiagofalcao/ArchC,lianaduenha/ArchC,tiagofalcao/ArchC,tiagofalcao/ArchC,tiagofalcao/ArchC,tiagofalcao/ArchC,tiagofalcao/ArchC,lianaduenha/ArchC,tiagofalcao/ArchC,lianaduenha/ArchC