Rename CMake option ZLIB to protobuf_WITH_ZLIB

cmake/CMakeLists.txt

@@ -13,11 +13,11 @@ option(protobuf_BUILD_TESTS "Build tests" ON)
 option(BUILD_SHARED_LIBS "Build Shared Libraries" OFF)
 option(protobuf_MSVC_STATIC_RUNTIME "Link static runtime libraries" ON)
 if (MSVC)
-  set(ZLIB_DEFAULT OFF)
+  set(protobuf_WITH_ZLIB_DEFAULT OFF)
 else (MSVC)
-  set(ZLIB_DEFAULT ON)
+  set(protobuf_WITH_ZLIB_DEFAULT ON)
 endif (MSVC)
-option(ZLIB "Build with zlib support" ${ZLIB_DEFAULT})
+option(protobuf_WITH_ZLIB "Build with zlib support" ${protobuf_WITH_ZLIB_DEFAULT})
 
 # Path to main configure script
 set(protobuf_CONFIGURE_SCRIPT "../configure.ac")
@@ -63,7 +63,7 @@ if (CMAKE_USE_PTHREADS_INIT)
   add_definitions(-DHAVE_PTHREAD)
 endif (CMAKE_USE_PTHREADS_INIT)
 
-if (ZLIB)
+if (protobuf_WITH_ZLIB)
   find_package(ZLIB)
   if (ZLIB_FOUND)
     set(HAVE_ZLIB 1)
@@ -81,7 +81,7 @@ if (ZLIB)
     set(ZLIB_INCLUDE_DIRECTORIES)
     set(ZLIB_LIBRARIES)
   endif (ZLIB_FOUND)
-endif (ZLIB)
+endif (protobuf_WITH_ZLIB)
 
 if (HAVE_ZLIB)
   add_definitions(-DHAVE_ZLIB)