configure.ac: don't check for clock_ functions

They shouldn't be exposed on Windows and lead to winpthread being linked in

Author: lazka

configure.ac

@@ -5209,6 +5209,9 @@ WITH_SAVE_ENV([
   ])
 ])
 
+case $host in
+  *-*-mingw*) ;;
+  *)
 AC_CHECK_FUNCS(clock_gettime, [], [
     AC_CHECK_LIB(rt, clock_gettime, [
         LIBS="$LIBS -lrt"
@@ -5229,6 +5232,8 @@ AC_CHECK_FUNCS(clock_settime, [], [
         AC_DEFINE(HAVE_CLOCK_SETTIME, 1)
     ])
 ])
+  ;;
+esac
 
 AC_CHECK_FUNCS(clock_nanosleep, [], [
     AC_CHECK_LIB(rt, clock_nanosleep, [