Better error information when minizip or zlib wasn't found

src/CMakeLists.txt

@@ -175,7 +175,11 @@ if(ZLIB_FOUND AND MINIZIP_LIBRARY)
   add_definitions(-DHAVE_MINIZIP)
 else()
   if(ENABLE_CODECS)
-    message(FATAL_ERROR "minizip/zlib required in this configuration")
+    if (ZLIB_FOUND)
+      message(FATAL_ERROR "minizip required in this configuration")
+    else()
+      message(FATAL_ERROR "zlib required in this configuration")
+    endif()
   endif()
 endif()