diff --git a/packages/pngquant/configure.patch b/packages/pngquant/configure.patch
index ca031db49..d0c3ee307 100644
--- a/packages/pngquant/configure.patch
+++ b/packages/pngquant/configure.patch
@@ -1,3 +1,6 @@
+First part has been submitted upstream:
+https://github.com/kornelski/pngquant/pull/303
+
 diff -u -r ../pngquant-2.12.1/configure ./configure
 --- ../pngquant-2.12.1/configure	2018-06-04 11:30:47.000000000 +0000
 +++ ./configure	2018-07-02 11:53:11.547417517 +0000
@@ -9,7 +12,7 @@ diff -u -r ../pngquant-2.12.1/configure ./configure
 -        cflags "$(pkg-config --cflags "$LIBNAME")"
 -        lflags "$(pkg-config --libs "$LIBNAME")"
 -        LIBRARY_FOUND_VERSION=$(pkg-config --modversion "$LIBNAME")
-+    PKG_CONFIG=${PKG_CONFIG:pkg-config}
++    PKG_CONFIG=${PKG_CONFIG:-pkg-config}
 +    if $PKG_CONFIG --exists "$LIBNAME" &> /dev/null; then
 +        cflags "$($PKG_CONFIG --cflags "$LIBNAME")"
 +        lflags "$($PKG_CONFIG --libs "$LIBNAME")"