Add a macro to probe -mwindows on MinGW.

[dxcommon.git] / m4 / w32gui.m4

diff --git a/m4/w32gui.m4 b/m4/w32gui.m4
new file mode 100644 (file)
index 0000000..f333015
--- /dev/null
+++ b/m4/w32gui.m4
@@ -0,0 +1,32 @@
+dnl Copyright © 2022 Nick Bowler
+dnl
+dnl License WTFPL2: Do What The Fuck You Want To Public License, version 2.
+dnl This is free software: you are free to do what the fuck you want to.
+dnl There is NO WARRANTY, to the extent permitted by law.
+
+dnl DX_W32_GUI
+dnl
+dnl Determine the C linker options needed to build a Windows graphical
+dnl application (i.e., for the "windows" subsystem).  The result is saved
+dnl in the cache variable dx_cv_w32_gui_flags.
+dnl
+dnl If no suitable flags could be determined, the cache variable dx_cv_w32_gui
+dnl is set to "unknown" and dx_cv_w32_gui_flags is set to the empty string.
+
+AC_DEFUN([DX_W32_GUI], [AC_REQUIRE([AC_PROG_AWK])dnl
+AC_CACHE_CHECK([for $CC option to target W32 GUI], [dx_cv_w32_gui],
+[_dx_check_pe_subsys () {
+  $AWK -f m4_do([m4_pushdef([m4_include], [$][1])],
+                [m4_include(DX_BASEDIR[/scripts/pe-subsys.awk])],
+                [m4_popdef([m4_include])]) "conftest$EXEEXT"
+}
+dx_cv_w32_gui=unknown _dx_save_LDFLAGS=$LDFLAGS
+for dx_cv_w32_gui_flags in '' -mwindows; do
+LDFLAGS="$_dx_save_LDFLAGS $dx_cv_w32_gui_flags"
+AC_LINK_IFELSE([AC_LANG_PROGRAM],
+[AS_CASE([`_dx_check_pe_subsys`],
+[gui], [dx_cv_w32_gui=${dx_cv_w32_gui_flags:-none needed}; break]
+)])
+done
+test x"$dx_cv_w32_gui" != x"unknown" || dx_cv_w32_gui_flags=
+LDFLAGS=$_dx_save_LDFLAGS])])