[gn build] Manually port 89d636b

Author: aeubanks

llvm/utils/gn/secondary/llvm/include/llvm/Config/BUILD.gn

@@ -137,12 +137,14 @@ write_cmake_config("config") {
   if (current_os == "linux" || current_os == "android") {
     values += [
       "HAVE_FUTIMENS=1",
+      "HAVE_GETAUXVAL=1",
       "HAVE_MALLINFO=1",
       "HAVE_STRUCT_STAT_ST_MTIM_TV_NSEC=1",
     ]
   } else {
     values += [
       "HAVE_FUTIMENS=",
+      "HAVE_GETAUXVAL=",
       "HAVE_MALLINFO=",
       "HAVE_STRUCT_STAT_ST_MTIM_TV_NSEC=",
     ]