[PATCH] libstdc++: detect DLLs on windows with <stacktrace>

[Björn Schäpers]

From: Björn Schäpers <bjoern@hazardy.de>

libstdc++-v3/Changelog

	* acinclude.m4 (GLIBCXX_ENABLE_BACKTACE): Add check for
	  tlhelp32.h, matching libbacktrace.
	* configure: Regenerate.
	* config.h.in: Regenerate.

Signed-off-by: Björn Schäpers <bjoern@hazardy.de>
---
 libstdc++-v3/acinclude.m4 |  4 ++++
 libstdc++-v3/config.h.in  |  3 +++
 libstdc++-v3/configure    | 15 +++++++++++++++
 3 files changed, 22 insertions(+)

diff --git a/libstdc++-v3/acinclude.m4 b/libstdc++-v3/acinclude.m4
index 51a08bcc8b1..506ce98ae43 100644
--- a/libstdc++-v3/acinclude.m4
+++ b/libstdc++-v3/acinclude.m4
@@ -5481,6 +5481,10 @@ AC_DEFUN([GLIBCXX_ENABLE_BACKTRACE], [
     BACKTRACE_CPPFLAGS="$BACKTRACE_CPPFLAGS -DHAVE_DL_ITERATE_PHDR=1"
   fi
   AC_CHECK_HEADERS(windows.h)
+  AC_CHECK_HEADERS(tlhelp32.h, [], [],
+  [#ifdef HAVE_WINDOWS_H
+  #  include <windows.h>
+  #endif])
 
   # Check for the fcntl function.
   if test -n "${with_target_subdir}"; then
diff --git a/libstdc++-v3/config.h.in b/libstdc++-v3/config.h.in
index 906e0143099..486ba450749 100644
--- a/libstdc++-v3/config.h.in
+++ b/libstdc++-v3/config.h.in
@@ -490,6 +490,9 @@
 /* Define to 1 if you have the `timespec_get' function. */
 #undef HAVE_TIMESPEC_GET
 
+/* Define to 1 if you have the <tlhelp32.h> header file. */
+#undef HAVE_TLHELP32_H
+
 /* Define to 1 if the target supports thread-local storage. */
 #undef HAVE_TLS
 
diff --git a/libstdc++-v3/configure b/libstdc++-v3/configure
index 21abaeb0778..a2d59520146 100755
--- a/libstdc++-v3/configure
+++ b/libstdc++-v3/configure
@@ -53865,6 +53865,21 @@ _ACEOF
 
 fi
 
+done
+
+  for ac_header in tlhelp32.h
+do :
+  ac_fn_c_check_header_compile "$LINENO" "tlhelp32.h" "ac_cv_header_tlhelp32_h" "#ifdef HAVE_WINDOWS_H
+  #  include <windows.h>
+  #endif
+"
+if test "x$ac_cv_header_tlhelp32_h" = xyes; then :
+  cat >>confdefs.h <<_ACEOF
+#define HAVE_TLHELP32_H 1
+_ACEOF
+
+fi
+
 done
 
 
-- 
2.44.0