We still need to update pkgconfig variables when zlib is unbundled (#5079).

src/CMakeLists.txt

@@ -327,6 +327,11 @@ IF(NOT USE_BUNDLED_ZLIB)
 	IF(ZLIB_FOUND)
 		LIST(APPEND LIBGIT2_SYSTEM_INCLUDES ${ZLIB_INCLUDE_DIRS})
 		LIST(APPEND LIBGIT2_LIBS ${ZLIB_LIBRARIES})
+        IF(APPLE OR CMAKE_SYSTEM_NAME MATCHES "FreeBSD")
+            LIST(APPEND LIBGIT2_PC_LIBS "-lz")
+        ELSE()
+            LIST(APPEND LIBGIT2_PC_REQUIRES "zlib")
+        ENDIF()
 		ADD_FEATURE_INFO(zlib ON "using system zlib")
 	ELSE()
 		MESSAGE(STATUS "zlib was not found; using bundled 3rd-party sources." )