message: Don't link libm with -Wl,--as-needed on FreeBSD
  Patch by jbeich (Jan Beich)
diff: @@ -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})
  