diff --git a/src/wxcommon/libpng/Makefile.in b/src/wxcommon/libpng/Makefile.in
index 59624bc523..5d5058dd7e 100644
--- a/src/wxcommon/libpng/Makefile.in
+++ b/src/wxcommon/libpng/Makefile.in
@@ -20,6 +20,7 @@ DESTDIR=
 # Where the zlib library and include files are located
 #ZLIBINC=/usr/local/include
 ZLIBINC=@ZLIB_INC@
+ZLIB_INC = -I$(srcdir)/../zlib
 
 CFLAGS=@CFLAGS@ @PREFLAGS@ @COMPFLAGS@ @OPTIONS@ @MROPTIONS@ $(ZLIBINC)