Require gtk+3 3.0.0 and drop checks for minor versions.

configure.ac

@@ -64,7 +64,7 @@ CLUTTER_MIN_VERSION=1.5.15
 GOBJECT_INTROSPECTION_MIN_VERSION=0.10.1
 GJS_MIN_VERSION=0.7.11
 MUTTER_MIN_VERSION=2.91.4
-GTK_MIN_VERSION=2.99.3
+GTK_MIN_VERSION=3.0.0
 GIO_MIN_VERSION=2.25.9
 LIBECAL_REQUIRED=1.6.0
 LIBEDATASERVER_REQUIRED=1.2.0

src/shell-doc-system.c

@@ -261,11 +261,7 @@ shell_doc_system_open (ShellDocSystem *system,
   else
     {
       char *app_name;
-#if GTK_MINOR_VERSION >= 18
       const char *app_exec;
-#else
-      char *app_exec;
-#endif
       char *app_exec_quoted;
       guint count;
       time_t time;