Commit 9ac9b6b for zlib

commit 9ac9b6bb2d1858e1d95561642f672798deb5c5f4
Author: Ross Burton <ross.burton@arm.com>
Date:   Mon Jul 18 17:02:37 2022 +0100

    Fix the minizip Makefile to use the default variables and rules.

diff --git a/contrib/minizip/Makefile b/contrib/minizip/Makefile
index b3e050a..f5f65f7 100644
--- a/contrib/minizip/Makefile
+++ b/contrib/minizip/Makefile
@@ -1,12 +1,8 @@
-CC?=cc
-CFLAGS := -O $(CFLAGS) -I../..
+CPPFLAGS = -I../..

 UNZ_OBJS = miniunz.o unzip.o ioapi.o ../../libz.a
 ZIP_OBJS = minizip.o zip.o   ioapi.o ../../libz.a

-.c.o:
-	$(CC) -c $(CFLAGS) $*.c
-
 all: miniunz minizip

 miniunz.o: miniunz.c unzip.h iowin32.h
@@ -18,10 +14,8 @@ iowin32.o: iowin32.c iowin32.h ioapi.h
 mztools.o: mztools.c unzip.h

 miniunz: $(UNZ_OBJS)
-	$(CC) $(CFLAGS) -o $@ $(UNZ_OBJS)

 minizip: $(ZIP_OBJS)
-	$(CC) $(CFLAGS) -o $@ $(ZIP_OBJS)

 test: miniunz minizip
 	@rm -f test.*