Add std::timespec and std::timespec_get for C++17

* configure.ac: Check for C11 timespec_get function.
	* crossconfig.m4 (freebsd, linux, gnu, cygwin, solaris, netbsd)
	(openbsd): Likewise
	* config.h.in: Regenerate.
	* configure: Regenerate.
	* include/c_global/ctime (timespec, timespec_get): Add to namespace
	std for C++17 and up.

From-SVN: r268879

libstdc++-v3/ChangeLog

@@ -1,5 +1,13 @@
 2019-02-14  Jonathan Wakely  <jwakely@redhat.com>
 
+	* configure.ac: Check for C11 timespec_get function.
+	* crossconfig.m4 (freebsd, linux, gnu, cygwin, solaris, netbsd)
+	(openbsd): Likewise
+	* config.h.in: Regenerate.
+	* configure: Regenerate.
+	* include/c_global/ctime (timespec, timespec_get): Add to namespace
+	std for C++17 and up.
+
 	* doc/xml/manual/intro.xml: Document LWG 2537 status.
 	* include/bits/stl_queue.h
 	(priority_queue(const Compare&, const Container&, const Alloc&))

libstdc++-v3/config.h.in

@@ -508,6 +508,9 @@
 /* Define to 1 if you have the <tgmath.h> header file. */
 #undef HAVE_TGMATH_H
 
+/* Define to 1 if you have the `timespec_get' function. */
+#undef HAVE_TIMESPEC_GET
+
 /* Define to 1 if the target supports thread-local storage. */
 #undef HAVE_TLS
 

libstdc++-v3/configure

@@ -28428,6 +28428,19 @@ if test "x$ac_cv_func__wfopen" = xyes; then :
 #define HAVE__WFOPEN 1
 _ACEOF
 
+fi
+done
+
+
+  # C11 functions for C++17 library
+  for ac_func in timespec_get
+do :
+  ac_fn_c_check_func "$LINENO" "timespec_get" "ac_cv_func_timespec_get"
+if test "x$ac_cv_func_timespec_get" = xyes; then :
+  cat >>confdefs.h <<_ACEOF
+#define HAVE_TIMESPEC_GET 1
+_ACEOF
+
 fi
 done
 
@@ -53613,6 +53626,17 @@ if eval test \"x\$"$as_ac_var"\" = x"yes"; then :
 #define `$as_echo "HAVE_$ac_func" | $as_tr_cpp` 1
 _ACEOF
 
+fi
+done
+
+    for ac_func in timespec_get
+do :
+  ac_fn_c_check_func "$LINENO" "timespec_get" "ac_cv_func_timespec_get"
+if test "x$ac_cv_func_timespec_get" = xyes; then :
+  cat >>confdefs.h <<_ACEOF
+#define HAVE_TIMESPEC_GET 1
+_ACEOF
+
 fi
 done
 
@@ -60232,6 +60256,17 @@ _ACEOF
 fi
 done
 
+    for ac_func in timespec_get
+do :
+  ac_fn_c_check_func "$LINENO" "timespec_get" "ac_cv_func_timespec_get"
+if test "x$ac_cv_func_timespec_get" = xyes; then :
+  cat >>confdefs.h <<_ACEOF
+#define HAVE_TIMESPEC_GET 1
+_ACEOF
+
+fi
+done
+
 
 
 
@@ -66542,6 +66577,17 @@ if eval test \"x\$"$as_ac_var"\" = x"yes"; then :
 #define `$as_echo "HAVE_$ac_func" | $as_tr_cpp` 1
 _ACEOF
 
+fi
+done
+
+    for ac_func in timespec_get
+do :
+  ac_fn_c_check_func "$LINENO" "timespec_get" "ac_cv_func_timespec_get"
+if test "x$ac_cv_func_timespec_get" = xyes; then :
+  cat >>confdefs.h <<_ACEOF
+#define HAVE_TIMESPEC_GET 1
+_ACEOF
+
 fi
 done
 

libstdc++-v3/configure.ac

@@ -265,6 +265,9 @@ if $GLIBCXX_IS_NATIVE; then
   AC_CHECK_FUNCS(aligned_alloc posix_memalign memalign _aligned_malloc)
   AC_CHECK_FUNCS(_wfopen)
 
+  # C11 functions for C++17 library
+  AC_CHECK_FUNCS(timespec_get)
+
   # For iconv support.
   AM_ICONV
 

libstdc++-v3/crossconfig.m4

@@ -135,6 +135,7 @@ case "${host}" in
     fi
     AC_CHECK_FUNCS(__cxa_thread_atexit)
     AC_CHECK_FUNCS(aligned_alloc posix_memalign memalign _aligned_malloc)
+    AC_CHECK_FUNCS(timespec_get)
     ;;
 
   *-fuchsia*)
@@ -194,6 +195,7 @@ case "${host}" in
     GCC_CHECK_TLS
     AC_CHECK_FUNCS(__cxa_thread_atexit_impl)
     AC_CHECK_FUNCS(aligned_alloc posix_memalign memalign _aligned_malloc)
+    AC_CHECK_FUNCS(timespec_get)
     AM_ICONV
     ;;
   *-mingw32*)
@@ -221,6 +223,7 @@ case "${host}" in
       AC_DEFINE(HAVE_ISNANL)
     fi
     AC_CHECK_FUNCS(aligned_alloc posix_memalign memalign _aligned_malloc)
+    AC_CHECK_FUNCS(timespec_get)
     ;;
   *-qnx6.1* | *-qnx6.2*)
     SECTION_FLAGS='-ffunction-sections -fdata-sections'

libstdc++-v3/include/c_global/ctime

@@ -72,4 +72,13 @@ namespace std
   using ::strftime;
 } // namespace
 
+#if __cplusplus >= 201703L && defined(_GLIBCXX_HAVE_TIMESPEC_GET)
+#undef timespec_get
+namespace std
+{
+  using ::timespec;
+  using ::timespec_get;
+} // namespace std
+#endif
+
 #endif