[binutils-gdb/gdb-13-branch] Set _WIN32_WINNT in common.m4 configure check

[binutils-gdb/gdb-13-branch] Set _WIN32_WINNT in common.m4 configure check

[Tom Tromey]

https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=3cc048fc6b1f29ea7f5de83815e56884bbd05f61

commit 3cc048fc6b1f29ea7f5de83815e56884bbd05f61
Author: Tom Tromey <tromey@adacore.com>
Date:   Mon Jan 9 07:43:29 2023 -0700

    Set _WIN32_WINNT in common.m4 configure check
    
    GCC recently added support for the Windows thread model, enabling
    libstdc++ to support Windows natively.  However, this supporrt
    requires a version of Windows later than the minimum version that is
    supported by GDB.
    
    PR build/29966 points out that the GDB configure test for std::thread
    does not work in this situation, because _WIN32_WINNT is not defined
    in test program, and so <thread> seems to be fine.
    
    This patch is an attempt to fix the problem, by using the same setting
    for _WIN32_WINNT at configure time as is used at build time.
    
    I don't have access to one of the older systems so I don't think I can
    truly test this.  I did do a mingw cross build, though.  I'm going to
    ask the bug reporter to test it.
    
    Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=29966
    
    (cherry picked from commit 2124b2de4bba05063218501dcccfc4cffe648cda)

Diff:
---
 gdb/configure            | 12 +++++++++++-
 gdbserver/configure      | 12 +++++++++++-
 gdbsupport/common-defs.h |  4 +++-
 gdbsupport/common.m4     | 13 ++++++++++++-
 gdbsupport/configure     | 12 +++++++++++-
 5 files changed, 48 insertions(+), 5 deletions(-)

diff --git a/gdb/configure b/gdb/configure
index 23e6b7160ec..bdea17043b5 100755
--- a/gdb/configure
+++ b/gdb/configure
@@ -25967,7 +25967,17 @@ if ${gdb_cv_cxx_std_thread+:} false; then :
 else
   cat confdefs.h - <<_ACEOF >conftest.$ac_ext
 /* end confdefs.h.  */
-#include <thread>
+  #if defined (__MINGW32__) || defined (__CYGWIN__)
+    # ifdef _WIN32_WINNT
+    #  if _WIN32_WINNT < 0x0501
+    #   undef _WIN32_WINNT
+    #   define _WIN32_WINNT 0x0501
+    #  endif
+    # else
+    #  define _WIN32_WINNT 0x0501
+    # endif
+    #endif	/* __MINGW32__ || __CYGWIN__ */
+    #include <thread>
     void callback() { }
 int
 main ()
diff --git a/gdbserver/configure b/gdbserver/configure
index 050264ed7da..6dc6b1ff6ad 100755
--- a/gdbserver/configure
+++ b/gdbserver/configure
@@ -7941,7 +7941,17 @@ if ${gdb_cv_cxx_std_thread+:} false; then :
 else
   cat confdefs.h - <<_ACEOF >conftest.$ac_ext
 /* end confdefs.h.  */
-#include <thread>
+  #if defined (__MINGW32__) || defined (__CYGWIN__)
+    # ifdef _WIN32_WINNT
+    #  if _WIN32_WINNT < 0x0501
+    #   undef _WIN32_WINNT
+    #   define _WIN32_WINNT 0x0501
+    #  endif
+    # else
+    #  define _WIN32_WINNT 0x0501
+    # endif
+    #endif	/* __MINGW32__ || __CYGWIN__ */
+    #include <thread>
     void callback() { }
 int
 main ()
diff --git a/gdbsupport/common-defs.h b/gdbsupport/common-defs.h
index bcebd7187d9..5e529f6febf 100644
--- a/gdbsupport/common-defs.h
+++ b/gdbsupport/common-defs.h
@@ -70,7 +70,9 @@
 
 /* We don't support Windows versions before XP, so we define
    _WIN32_WINNT correspondingly to ensure the Windows API headers
-   expose the required symbols.  */
+   expose the required symbols.
+
+   NOTE: this must be kept in sync with common.m4.  */
 #if defined (__MINGW32__) || defined (__CYGWIN__)
 # ifdef _WIN32_WINNT
 #  if _WIN32_WINNT < 0x0501
diff --git a/gdbsupport/common.m4 b/gdbsupport/common.m4
index 7b100262c29..b3aa27185ea 100644
--- a/gdbsupport/common.m4
+++ b/gdbsupport/common.m4
@@ -100,7 +100,18 @@ AC_DEFUN([GDB_AC_COMMON], [
   AC_CACHE_CHECK([for std::thread],
 		 gdb_cv_cxx_std_thread,
 		 [AC_COMPILE_IFELSE([AC_LANG_PROGRAM(
-  [[#include <thread>
+  dnl NOTE: this must be kept in sync with common-defs.h.
+  [[#if defined (__MINGW32__) || defined (__CYGWIN__)
+    # ifdef _WIN32_WINNT
+    #  if _WIN32_WINNT < 0x0501
+    #   undef _WIN32_WINNT
+    #   define _WIN32_WINNT 0x0501
+    #  endif
+    # else
+    #  define _WIN32_WINNT 0x0501
+    # endif
+    #endif	/* __MINGW32__ || __CYGWIN__ */
+    #include <thread>
     void callback() { }]],
   [[std::thread t(callback);]])],
 				gdb_cv_cxx_std_thread=yes,
diff --git a/gdbsupport/configure b/gdbsupport/configure
index 38541e87c15..44dd8a9f704 100755
--- a/gdbsupport/configure
+++ b/gdbsupport/configure
@@ -8957,7 +8957,17 @@ if ${gdb_cv_cxx_std_thread+:} false; then :
 else
   cat confdefs.h - <<_ACEOF >conftest.$ac_ext
 /* end confdefs.h.  */
-#include <thread>
+  #if defined (__MINGW32__) || defined (__CYGWIN__)
+    # ifdef _WIN32_WINNT
+    #  if _WIN32_WINNT < 0x0501
+    #   undef _WIN32_WINNT
+    #   define _WIN32_WINNT 0x0501
+    #  endif
+    # else
+    #  define _WIN32_WINNT 0x0501
+    # endif
+    #endif	/* __MINGW32__ || __CYGWIN__ */
+    #include <thread>
     void callback() { }
 int
 main ()