package/libvips: add zlib optional dependency

zlib is an optional dependency which is enabled by default since version
8.4.2 and
https://github.com/libvips/libvips/commit/5ab0001ec68a5f61396aecd8d2d7a619b1dbe1fa

Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
(cherry picked from commit 43a9cfd31781777753bc3f8b1a36996d16583e47)
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

package/libvips/libvips.mk

@@ -96,4 +96,11 @@ else
 LIBVIPS_CONF_OPTS += --without-libexif
 endif
 
+ifeq ($(BR2_PACKAGE_ZLIB),y)
+LIBVIPS_CONF_OPTS += --with-zlib
+LIBVIPS_DEPENDENCIES += zlib
+else
+LIBVIPS_CONF_OPTS += --without-zlib
+endif
+
 $(eval $(autotools-package))