[OpenMP] Fix the check for libpsapi for i386

[mstorsjo]

Summary

check_library_exists fails for stdcall functions, because that check doesn't include the necessary headers (and thus fails with an undefined reference to _EnumProcessModules, when the import library symbol actually is called _EnumProcessModules@16).

Merge the two previous checks check_include_files and check_library_exists into one with check_c_source_compiles, and merge the variables that indicate whether it succeeded.

[AndreyChurbanov]

LGTM

openmp/runtime/cmake/LibompHandleFlags.cmake

 function(libomp_get_libflags libflags)
   set(libflags_local)
   libomp_append(libflags_local "${CMAKE_THREAD_LIBS_INIT}")
   libomp_append(libflags_local "${LIBOMP_HWLOC_LIBRARY}" LIBOMP_USE_HWLOC)
   if(${IA32})
     libomp_append(libflags_local -lirc_pic LIBOMP_HAVE_IRC_PIC_LIBRARY)
   endif()
   if(MINGW)
-    libomp_append(libflags_local -lpsapi LIBOMP_HAVE_LIBPSAPI)
+    libomp_append(libflags_local -lpsapi LIBOMP_HAVE_PSAPI)
   endif()
   if(LIBOMP_HAVE_SHM_OPEN_WITH_LRT)
     libomp_append(libflags_local -lrt)
   endif()
   if(${CMAKE_SYSTEM_NAME} MATCHES "DragonFly|FreeBSD")
     libomp_append(libflags_local "-Wl,--no-as-needed" LIBOMP_HAVE_AS_NEEDED_FLAG)
     libomp_append(libflags_local "-lm")
     libomp_append(libflags_local "-Wl,--as-needed" LIBOMP_HAVE_AS_NEEDED_FLAG)

openmp/runtime/cmake/config-ix.cmake

 # Currently, __builtin_frame_address() is required for OMPT
 # Weak attribute is required for Unices (except Darwin), LIBPSAPI is used for Windows
 check_c_source_compiles("int main(int argc, char** argv) {
   void* p = __builtin_frame_address(0);
   return 0;}" LIBOMP_HAVE___BUILTIN_FRAME_ADDRESS)
 check_c_source_compiles("__attribute__ ((weak)) int foo(int a) { return a*a; }
   int main(int argc, char** argv) {
   return foo(argc);}" LIBOMP_HAVE_WEAK_ATTRIBUTE)
-check_include_files("windows.h;psapi.h" LIBOMP_HAVE_PSAPI_H)
-check_library_exists(psapi EnumProcessModules "" LIBOMP_HAVE_LIBPSAPI)
-if(LIBOMP_HAVE_PSAPI_H AND LIBOMP_HAVE_LIBPSAPI)
-  set(LIBOMP_HAVE_PSAPI TRUE)
-endif()
+set(CMAKE_REQUIRED_LIBRARIES psapi)
+check_c_source_compiles("#include <windows.h>
+  #include <psapi.h>
+  int main(int artc, char** argv) {
+    return EnumProcessModules(NULL, NULL, 0, NULL);
+  }" LIBOMP_HAVE_PSAPI)
+set(CMAKE_REQUIRED_LIBRARIES)
 if(NOT LIBOMP_HAVE___BUILTIN_FRAME_ADDRESS)
   set(LIBOMP_HAVE_OMPT_SUPPORT FALSE)
 else()
   if( # hardware architecture supported?
      ((LIBOMP_ARCH STREQUAL x86_64) OR
       (LIBOMP_ARCH STREQUAL i386) OR
 #      (LIBOMP_ARCH STREQUAL arm) OR
       (LIBOMP_ARCH STREQUAL aarch64) OR