Refactor: move gtk detection to own header

src/detection/gtk.c

@@ -1,4 +1,5 @@
 #include "fastfetch.h"
+#include "detection/gtk.h"
 #include "common/properties.h"
 #include "common/settings.h"
 

src/detection/gtk.h

@@ -0,0 +1,21 @@
+#pragma once
+
+#ifndef FF_INCLUDED_detection_gtk
+#define FF_INCLUDED_detection_gtk
+
+#include "util/FFstrbuf.h"
+
+typedef struct FFGTKResult
+{
+    FFstrbuf theme;
+    FFstrbuf icons;
+    FFstrbuf font;
+    FFstrbuf cursor;
+    FFstrbuf cursorSize;
+} FFGTKResult;
+
+const FFGTKResult* ffDetectGTK2(FFinstance* instance);
+const FFGTKResult* ffDetectGTK4(FFinstance* instance);
+const FFGTKResult* ffDetectGTK3(FFinstance* instance);
+
+#endif