meson, app, build: Fix Inno wrongly allowing to unninstall with GIMP running

Inno needs an AppMutex to be aware of GIMP execution so
prevent unninstalling or installing GIMP if still running.

(Unninstalling with GIMP running was making GIMP to not be
fully unninstaled since gimp*.exe process file was opened.
It also could cause problems with settings unninstall.)

(Installing with GIMP running was already not possible
since Inno code in that part is more refined but
that check isn't done before deleting .debug files)

app/main.c

@@ -595,6 +595,15 @@ main (int    argc,
   gimp_init_signal_handlers (&backtrace_file);
 
 #ifdef G_OS_WIN32
+  /* Make Inno aware of gimp process avoiding broken install/unninstall */
+  char    *utf8_name = g_strdup_printf ("GIMP-%s", GIMP_MUTEX_VERSION);
+  wchar_t *name      = g_utf8_to_utf16 (utf8_name, -1, NULL, NULL, NULL);
+  
+  CreateMutexW (NULL, FALSE, name);
+  
+  g_free (utf8_name);
+  g_free (name);
+  
   /* Enable Anti-Aliasing*/
   g_setenv ("PANGOCAIRO_BACKEND", "fc", TRUE);
 

build/windows/installer/base_gimp3264.iss

@@ -129,7 +129,9 @@ NotRecognizedMessagesWarning=no
 
 
 ;3.2.1 INNO INTERNAL VERSIONING (used to rule how different versions are installed)
-;Inno installer identifier: https://github.com/jrsoftware/issrc/pull/461
+;GIMP process identifier for Inno
+AppMutex=GIMP-{#GIMP_MUTEX_VERSION}
+;Inno installer identifier
 SetupMutex=GIMP-{#GIMP_MUTEX_VERSION}
 ;Inno installer (default) install location
 DefaultDirName={autopf}\GIMP {#GIMP_MUTEX_VERSION}

meson.build

@@ -103,6 +103,13 @@ endif
 # GIMP_IS_GIT can only be set during development of a RC.
 conf.set('GIMP_IS_RC_GIT', gimp_rc_git ? 1 : false)
 
+# Mutex version
+if gimp_unstable != false
+  conf.set_quoted('GIMP_MUTEX_VERSION', gimp_app_version)
+else
+  conf.set_quoted('GIMP_MUTEX_VERSION', gimp_app_version_major.to_string())
+endif
+
 versionconfig = configuration_data()
 versionconfig.set('GIMP_FULL_NAME',     full_name)
 versionconfig.set('GIMP_MAJOR_VERSION', gimp_app_version_major)