Compilers are hardcoded to be gcc and gfortran

[spencerkclark]

Currently the C and fortran compilers are hardcoded to be gcc and gfortran:

call_py_fort/CMakeLists.txt

Lines 8 to 9 in 04ed791

	set(CMAKE_C_COMPILER gcc)
	set(CMAKE_Fortran_COMPILER gfortran)

This interferes with building on systems that use different compilers. The solution is probably to have comparable set calls within the Intel and PGI branches of the if-block that set the compilers to icc / ifort and pgcc / pgfortran respectively.