[OpenMP] Remove obsolete Fortran module file

Modern Fortran compilers support Fortran 90, so we do not need to use
the source code for Fortran compilers that do not support Fortran 90.

Differential Revision: https://reviews.llvm.org/D90077

Author: hansangbae

openmp/runtime/src/CMakeLists.txt

@@ -239,7 +239,6 @@ endif()
 # One compilation step creates both omp_lib.mod and omp_lib_kinds.mod
 if(${LIBOMP_FORTRAN_MODULES})
   configure_file(${LIBOMP_INC_DIR}/omp_lib.h.var omp_lib.h @ONLY)
-  configure_file(${LIBOMP_INC_DIR}/omp_lib.f.var omp_lib.f @ONLY)
   configure_file(${LIBOMP_INC_DIR}/omp_lib.f90.var omp_lib.f90 @ONLY)
   # Workaround for gfortran to build modules with the
   # omp_sched_monotonic integer parameter
@@ -251,7 +250,7 @@ if(${LIBOMP_FORTRAN_MODULES})
   if(CMAKE_Fortran_COMPILER_SUPPORTS_F90)
     set(LIBOMP_FORTRAN_SOURCE_FILE omp_lib.f90)
   else()
-    set(LIBOMP_FORTRAN_SOURCE_FILE omp_lib.f)
+    message(FATAL_ERROR "Fortran module build requires Fortran 90 compiler")
   endif()
   add_custom_command(
     OUTPUT omp_lib.mod omp_lib_kinds.mod