diff --git a/CMake/FindExprTk.cmake b/CMake/FindExprTk.cmake
index 2886e7ed71..cb8a875725 100644
--- a/CMake/FindExprTk.cmake
+++ b/CMake/FindExprTk.cmake
@@ -24,7 +24,7 @@ if (ExprTk_INCLUDE_DIR)
   set(ExprTk_VERSION)
   foreach (_exprtk_version_line IN LISTS _exprtk_version_header)
     if ("${ExprTk_VERSION}" STREQUAL "")
-      string(REGEX MATCH "version = \"(2\.7[0-9.]+)\".*$" _exprtk_version_match "${_exprtk_version_line}")
+      string(REGEX MATCH [[version = "(2\.7[0-9.]+)".*$]] _exprtk_version_match "${_exprtk_version_line}")
       set(ExprTk_VERSION "${CMAKE_MATCH_1}")
     else ()
       string(REGEX MATCH "\"([0-9.]+)\".*$" _exprtk_version_match "${_exprtk_version_line}")