Fix caca.pc

Patch taken from upstream svn

extras/contrib/src/Makefile

@@ -1290,6 +1290,7 @@ libcaca-$(LIBCACA_VERSION).tar.gz:
 
 libcaca: libcaca-$(LIBCACA_VERSION).tar.gz
 	$(EXTRACT_GZ)
+	patch -p0 < Patches/libcaca-static.patch
 ifdef HAVE_DARWIN_OS
 	#remove me at next libcaca upgrade
 	patch -p0 < Patches/libcaca_driver_cocoa.diff

extras/contrib/src/Patches/libcaca-static.patch

+--- libcaca/caca/caca.pc.in (revision 2878)
++++ libcaca/caca/caca.pc.in (revision 3647)
+@@ -10,3 +10,4 @@
+ Conflicts: 
+ Libs: -L${libdir} -lcaca
++Libs.private: @ZLIB_LIBS@
+ Cflags: -I${includedir}