zlib 1.2.4 compatibility

auto/lib/zlib/make

diff --git a/auto/lib/zlib/make b/auto/lib/zlib/make
index 4d62b75..b874b04 100644
--- a/auto/lib/zlib/make
+++ b/auto/lib/zlib/make
@@ -53,7 +53,7 @@
 
 $ZLIB/libz.a:	$NGX_MAKEFILE
 	cd $ZLIB \\
-	&& \$(MAKE) clean \\
+	&& \$(MAKE) distclean \\
 	&& cp contrib/asm586/match.S . \\
 	&& CFLAGS="$ZLIB_OPT -DASMV" CC="\$(CC)" \\
 		./configure \\
@@ -70,7 +70,7 @@
 
 $ZLIB/libz.a:	$NGX_MAKEFILE
 	cd $ZLIB \\
-	&& \$(MAKE) clean \\
+	&& \$(MAKE) distclean \\
 	&& cp contrib/asm686/match.S . \\
 	&& CFLAGS="$ZLIB_OPT -DASMV" CC="\$(CC)" \\
 		./configure \\
@@ -103,7 +103,7 @@
 
 $ZLIB/libz.a:	$NGX_MAKEFILE
 	cd $ZLIB \\
-	&& \$(MAKE) clean \\
+	&& \$(MAKE) distclean \\
 	&& CFLAGS="$ZLIB_OPT" CC="\$(CC)" \\
 		./configure \\
 	&& \$(MAKE) libz.a