build,qt: Optionally build Qt 6 bindings with -mno-direct-extern-access

* configure.ac: Check if C++ compiler supports
-mno-direct-extern-access. Add option to enable building with
-mno-direct-extern-access.
* m4/ax_check_compile_flag.m4: New.
* m4/qt6.m4: Add -mno-direct-extern-access to GPGME_QT6_CFLAGS if
supported and requested.
--

This adds the possibility to build the Qt 6 bindings with the
-mno-direct-extern-access flag. This is required if Qt 6 was built with
this flag. This is a workaround for the lack of Qt 6's pkgconfig files
providing this flag if needed.

GnuPG-bug-id: 6696

1 files changed, 6 insertions, 0 deletions

diff --git a/m4/qt6.m4 b/m4/qt6.m4
index df9e2d52..f317eace 100644
--- a/m4/qt6.m4
+++ b/m4/qt6.m4
@@ -32,7 +32,13 @@ AC_DEFUN([FIND_QT6],
       have_qt6_libs="no";
     fi
   fi
+
   if test "$have_qt6_libs" = "yes"; then
+    if test "$have_no_direct_extern_access" = "yes" \
+       && test "$use_no_direct_extern_access" = "yes"; then
+      GPGME_QT6_CFLAGS="$GPGME_QT6_CFLAGS -mno-direct-extern-access"
+    fi
+
     dnl Check that a binary can actually be build with this qt.
     dnl pkg-config may be set up in a way that it looks also for libraries
     dnl of the build system and not only for the host system. In that case