--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/gcc/config/glibc-d.c	Thu Feb 13 11:34:05 2020 +0900
@@ -0,0 +1,64 @@
+/* Glibc support needed only by D front-end.
+   Copyright (C) 2017-2020 Free Software Foundation, Inc.
+
+GCC is free software; you can redistribute it and/or modify it under
+the terms of the GNU General Public License as published by the Free
+Software Foundation; either version 3, or (at your option) any later
+version.
+
+GCC is distributed in the hope that it will be useful, but WITHOUT ANY
+WARRANTY; without even the implied warranty of MERCHANTABILITY or
+FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+for more details.
+
+You should have received a copy of the GNU General Public License
+along with GCC; see the file COPYING3.  If not see
+<http://www.gnu.org/licenses/>.  */
+
+#include "config.h"
+#include "system.h"
+#include "coretypes.h"
+#include "tm.h"
+#include "memmodel.h"
+#include "tm_p.h"
+#include "d/d-target.h"
+#include "d/d-target-def.h"
+
+/* Implement TARGET_D_OS_VERSIONS for Glibc targets.  */
+
+static void
+glibc_d_os_builtins (void)
+{
+  d_add_builtin_version ("Posix");
+
+#define builtin_version(TXT) d_add_builtin_version (TXT)
+
+#ifdef GNU_USER_TARGET_D_OS_VERSIONS
+  GNU_USER_TARGET_D_OS_VERSIONS ();
+#endif
+
+#ifdef EXTRA_TARGET_D_OS_VERSIONS
+  EXTRA_TARGET_D_OS_VERSIONS ();
+#endif
+}
+
+/* Implement TARGET_D_CRITSEC_SIZE for Glibc targets.  */
+
+static unsigned
+glibc_d_critsec_size (void)
+{
+  /* This is the sizeof pthread_mutex_t.  */
+#ifdef GNU_USER_TARGET_D_CRITSEC_SIZE
+  return GNU_USER_TARGET_D_CRITSEC_SIZE;
+#else
+  return (POINTER_SIZE == 64) ? 40 : 24;
+#endif
+}
+
+#undef TARGET_D_OS_VERSIONS
+#define TARGET_D_OS_VERSIONS glibc_d_os_builtins
+
+#undef TARGET_D_CRITSEC_SIZE
+#define TARGET_D_CRITSEC_SIZE glibc_d_critsec_size
+
+struct gcc_targetdm targetdm = TARGETDM_INITIALIZER;