Explicitly set the Windows subsystem for ninja/VisualC

mesonbuild/backend/ninjabackend.py

@@ -2234,9 +2234,9 @@ rule FORTRAN_DEP_HACK%s
         if isinstance(target, build.Executable):
             # Currently only used with the Swift compiler to add '-emit-executable'
             commands += linker.get_std_exe_link_args()
-            # If gui_app, and that's significant on this platform
-            if target.gui_app and hasattr(linker, 'get_gui_app_args'):
-                commands += linker.get_gui_app_args()
+            # If gui_app is significant on this platform
+            if hasattr(linker, 'get_gui_app_args'):
+                commands += linker.get_gui_app_args(target.gui_app)
             # If export_dynamic, add the appropriate linker arguments
             if target.export_dynamic:
                 commands += linker.gen_export_dynamic_link_args(self.environment)

mesonbuild/compilers/c.py

@@ -1276,8 +1276,13 @@ class VisualStudioCCompiler(CCompiler):
     def linker_to_compiler_args(self, args):
         return ['/link'] + args
 
-    def get_gui_app_args(self):
-        return ['/SUBSYSTEM:WINDOWS']
+    def get_gui_app_args(self, value):
+        # the default is for the linker to guess the subsystem based on presence
+        # of main or WinMain symbols, so always be explicit
+        if value:
+            return ['/SUBSYSTEM:WINDOWS']
+        else:
+            return ['/SUBSYSTEM:CONSOLE']
 
     def get_pic_args(self):
         return [] # PIC is handled by the loader on Windows

mesonbuild/compilers/compilers.py

@@ -1277,8 +1277,8 @@ class GnuCompiler:
         # For other targets, discard the .def file.
         return []
 
-    def get_gui_app_args(self):
-        if self.gcc_type in (GCC_CYGWIN, GCC_MINGW):
+    def get_gui_app_args(self, value):
+        if self.gcc_type in (GCC_CYGWIN, GCC_MINGW) and value:
             return ['-mwindows']
         return []