Merge pull request #3157 from yeswalrus/fix-version-check

Fix CMake version check

cmake/protobuf-config-version.cmake.in

@@ -17,6 +17,7 @@ endif()
 
 set(PACKAGE_VERSION_COMPATIBLE TRUE) #Assume true until shown otherwise
 
+if(PACKAGE_FIND_VERSION) #Only perform version checks if one is given
   if(NOT PACKAGE_FIND_VERSION_MAJOR EQUAL "@protobuf_VERSION_MAJOR@")
     set(PACKAGE_VERSION_COMPATIBLE FALSE)
   elseif(PACKAGE_FIND_VERSION VERSION_GREATER PACKAGE_VERSION)
@@ -33,14 +34,15 @@ elseif(PACKAGE_FIND_VERSION VERSION_EQUAL PACKAGE_VERSION)
       set(PACKAGE_VERSION_COMPATIBLE FALSE)
     endif()
   endif()
+endif()
 
 # Check and save build options used to create this package
 macro(_check_and_save_build_option OPTION VALUE)
   if(DEFINED ${PACKAGE_FIND_NAME}_${OPTION} AND
-    NOT ${PACKAGE_FIND_NAME}_${OPTION} EQUAL VALUE)
+    NOT ${PACKAGE_FIND_NAME}_${OPTION} STREQUAL ${VALUE})
     set(PACKAGE_VERSION_UNSUITABLE TRUE)
   endif()
-  set(${PACKAGE_FIND_NAME}_${OPTION} ${VALUE})
+  set(${PACKAGE_FIND_NAME}_${OPTION} ${VALUE} PARENT_SCOPE)
 endmacro()
 _check_and_save_build_option(WITH_ZLIB @protobuf_WITH_ZLIB@)
 _check_and_save_build_option(MSVC_STATIC_RUNTIME @protobuf_MSVC_STATIC_RUNTIME@)