Don't link libm with -Wl,--as-needed on FreeBSD

Patch by jbeich (Jan Beich)

Differential Revision: https://reviews.llvm.org/D68051

git-svn-id: https://llvm.org/svn/llvm-project/openmp/trunk@374037 91177308-0d34-0410-b5e6-96231b3b80d8

Author: AndreyChurbanov

runtime/cmake/LibompHandleFlags.cmake

@@ -126,11 +126,11 @@ function(libomp_get_libflags libflags)
   if(${IA32})
     libomp_append(libflags_local -lirc_pic LIBOMP_HAVE_IRC_PIC_LIBRARY)
   endif()
-  if(${CMAKE_SYSTEM_NAME} MATCHES "DragonFly")
+  if(${CMAKE_SYSTEM_NAME} MATCHES "DragonFly|FreeBSD")
     libomp_append(libflags_local "-Wl,--no-as-needed" LIBOMP_HAVE_AS_NEEDED_FLAG)
     libomp_append(libflags_local "-lm")
     libomp_append(libflags_local "-Wl,--as-needed" LIBOMP_HAVE_AS_NEEDED_FLAG)
-  elseif(${CMAKE_SYSTEM_NAME} MATCHES "(Free|Net)BSD")
+  elseif(${CMAKE_SYSTEM_NAME} MATCHES "NetBSD")
     libomp_append(libflags_local -lm)
   endif()
   set(libflags_local ${libflags_local} ${LIBOMP_LIBFLAGS})