compat UPDATE macos supports timegm but is unable to find the symbol
diff --git a/CMakeModules/UseCompat.cmake b/CMakeModules/UseCompat.cmake
index c8daa2d..34a9741 100644
--- a/CMakeModules/UseCompat.cmake
+++ b/CMakeModules/UseCompat.cmake
@@ -51,7 +51,7 @@
     check_symbol_exists(realpath "stdlib.h" HAVE_REALPATH)
     check_symbol_exists(localtime_r "time.h" HAVE_LOCALTIME_R)
     check_symbol_exists(gmtime_r "time.h" HAVE_GMTIME_R)
-    check_symbol_exists(timegm "time.h" HAVE_TIMEGM)
+    check_function_exists(timegm HAVE_TIMEGM)
     check_symbol_exists(strptime "time.h" HAVE_STRPTIME)
     check_symbol_exists(mmap "sys/mman.h" HAVE_MMAP)
     check_symbol_exists(dirname "libgen.h" HAVE_DIRNAME)