Hack-fix build with different system/core/charger versions

Signed-off-by: Vojtech Bocek <vbocek@gmail.com>
diff --git a/minui/graphics.c b/minui/graphics.c
index 4968eac..9ee77b3 100644
--- a/minui/graphics.c
+++ b/minui/graphics.c
@@ -223,7 +223,12 @@
     *y = gr_font->cheight;
 }
 
-int gr_text(int x, int y, const char *s, int bold)
+int gr_text(int x, int y, const char *s, ...)
+{
+    return gr_text_impl(x, y, s, 0);
+}
+
+int gr_text_impl(int x, int y, const char *s, int bold)
 {
     GGLContext *gl = gr_context;
     GRFont *font = gr_font;