Don't build the Gnulib 'utimens' module on MinGW

* nt/gnulib-cfg.mk (OMIT_GNULIB_MODULE_utimens): Omit the
'utimens' module in the MinGW build: 'utimens' is not used by
Emacs, and 'fdutimens' is implemented in w32.c.

Author: Eli-Zaretskii

nt/gnulib-cfg.mk

@@ -63,3 +63,4 @@ OMIT_GNULIB_MODULE_sys_time = true
 OMIT_GNULIB_MODULE_sys_types = true
 OMIT_GNULIB_MODULE_unistd = true
 OMIT_GNULIB_MODULE_canonicalize-lgpl = true
+OMIT_GNULIB_MODULE_utimens = true