sokol.sapp,gg: add support for drag & drop events (#11359)

vlib/sokol/sapp/enums.v

@@ -23,6 +23,7 @@ pub enum EventType {
 	update_cursor
 	quit_requested
 	clipboard_pasted
+	files_droped
 	num
 }
 

vlib/sokol/sapp/sapp.c.v

@@ -245,3 +245,15 @@ pub fn toggle_fullscreen() {
 pub fn is_fullscreen() bool {
 	return C.sapp_is_fullscreen()
 }
+
+[inline]
+pub fn get_num_dropped_files() int {
+	return C.sapp_get_num_dropped_files()
+}
+
+[inline]
+pub fn get_dropped_file_path(index int) string {
+	unsafe {
+		return cstring_to_vstring(C.sapp_get_dropped_file_path(index))
+	}
+}

vlib/sokol/sapp/sapp_funcs.c.v

@@ -109,3 +109,9 @@ fn C.sapp_toggle_fullscreen()
 
 // Check if full screen rendering
 fn C.sapp_is_fullscreen() bool
+
+// Get number of droped files
+fn C.sapp_get_num_dropped_files() int
+
+// Get the file path of the droped file
+fn C.sapp_get_dropped_file_path(int) &byte