cmake/wsrep: allow disabling -DWITH_WSREP=OFF

cmake/wsrep.cmake

@@ -28,20 +28,20 @@ OPTION(WITH_WSREP_ALL
   "Build all components of WSREP (unit tests, sample programs)"
   OFF)
 
-# Set the patch version
-SET(WSREP_PATCH_VERSION "22")
+IF(WITH_WSREP)
+  # Set the patch version
+  SET(WSREP_PATCH_VERSION "22")
 
-# Obtain wsrep API version
-FILE(STRINGS "${CMAKE_SOURCE_DIR}/wsrep-lib/wsrep-API/v26/wsrep_api.h" WSREP_API_VERSION
-     LIMIT_COUNT 1 REGEX "WSREP_INTERFACE_VERSION")
-STRING(REGEX MATCH "([0-9]+)" WSREP_API_VERSION "${WSREP_API_VERSION}")
+  # Obtain wsrep API version
+  FILE(STRINGS "${CMAKE_SOURCE_DIR}/wsrep-lib/wsrep-API/v26/wsrep_api.h" WSREP_API_VERSION
+       LIMIT_COUNT 1 REGEX "WSREP_INTERFACE_VERSION")
+  STRING(REGEX MATCH "([0-9]+)" WSREP_API_VERSION "${WSREP_API_VERSION}")
 
-SET(WSREP_VERSION "${WSREP_API_VERSION}.${WSREP_PATCH_VERSION}"
-    CACHE INTERNAL "WSREP version")
+  SET(WSREP_VERSION "${WSREP_API_VERSION}.${WSREP_PATCH_VERSION}"
+      CACHE INTERNAL "WSREP version")
 
-SET(WSREP_PROC_INFO ${WITH_WSREP})
+  SET(WSREP_PROC_INFO ${WITH_WSREP})
 
-IF(WITH_WSREP)
   SET(WSREP_PATCH_VERSION "wsrep_${WSREP_VERSION}")
   if (NOT WITH_WSREP_ALL)
     SET(WSREP_LIB_WITH_UNIT_TESTS OFF CACHE BOOL