mingw-w64-cross-gcc: Fix configure options

mingw-w64-cross-gcc/PKGBUILD

@@ -190,9 +190,7 @@ build() {
     # use built-in SSP with Cygwin 2.10
     # FIXME: --disable-libssp should suffice in GCC 8
     export gcc_cv_libc_provides_ssp=yes
-    # configure tries to test SUSv4-compliant behaviour of
-    # realpath(..., NULL) via _XOPEN_VERSION
-    export glibcxx_cv_realpath=yes
+
     ../${_realname}-${pkgver}/configure \
       --prefix=/opt \
       --build=${CHOST} \
@@ -207,6 +205,7 @@ build() {
       --enable-threads=${_threads} \
       --enable-graphite \
       --enable-fully-dynamic-string \
+      --enable-libstdcxx-filesystem-ts=yes \
       --enable-libstdcxx-time=yes \
       --disable-libstdcxx-pch \
       --disable-libstdcxx-debug \