external: libpng: fix numerous compiler warnings

Clean up the code for unused variables to handle them
a bit more elegantly.

Change-Id: I8b01c27673128719dad74276599d5a286c4dd412

1 files changed, 1 insertions, 1 deletions

diff --git a/pngerror.c b/pngerror.c
index 025d52e..5b43790 100644
--- a/pngerror.c
+++ b/pngerror.c
@@ -348,7 +348,7 @@ png_default_warning(png_structp png_ptr, png_const_charp warning_message)
 #else
    warning_message = warning_message; /* Make compiler happy */
 #endif
-   png_ptr = png_ptr; /* Make compiler happy */
+   UNUSED(png_ptr); /* Make compiler happy */
 }
 #endif /* PNG_WARNINGS_SUPPORTED */