From 4a8920b1d4ea5e505edeb862dd27fb311673bef5 Mon Sep 17 00:00:00 2001
From: Gunnar Beutner <gunnar@beutner.name>
Date: Mon, 16 Mar 2015 13:31:33 +0100
Subject: [PATCH] Improve Flex version detection on Windows

refs #8750
---
 lib/config/CMakeLists.txt        | 4 ----
 third-party/cmake/FindFLEX.cmake | 8 +++++++-
 tools/mkclass/CMakeLists.txt     | 4 ----
 3 files changed, 7 insertions(+), 9 deletions(-)

diff --git a/lib/config/CMakeLists.txt b/lib/config/CMakeLists.txt
index 9b38981e5..52cbf5640 100644
--- a/lib/config/CMakeLists.txt
+++ b/lib/config/CMakeLists.txt
@@ -18,10 +18,6 @@
 find_package(BISON 2.3.0 REQUIRED)
 find_package(FLEX 2.5.31 REQUIRED)
 
-if("${FLEX_VERSION}" VERSION_LESS "2.5.31")
-    message(SEND_ERROR "Your version of flex is too old. You can specify an alternative path using -DFLEX_EXECUTABLE=/path/to/flex")
-endif()
-
 bison_target(config_parser config_parser.yy ${CMAKE_CURRENT_BINARY_DIR}/config_parser.cc)
 set_property(SOURCE ${CMAKE_CURRENT_BINARY_DIR}/config_parser.cc PROPERTY EXCLUDE_UNITY_BUILD TRUE)
 
diff --git a/third-party/cmake/FindFLEX.cmake b/third-party/cmake/FindFLEX.cmake
index df151fb36..cd54832c3 100644
--- a/third-party/cmake/FindFLEX.cmake
+++ b/third-party/cmake/FindFLEX.cmake
@@ -117,6 +117,12 @@ IF(FLEX_EXECUTABLE)
       FLEX_VERSION "${FLEX_version_output}")
   ENDIF()
 
+  IF(FLEX_FIND_VERSION)
+    IF("${FLEX_VERSION}" VERSION_LESS "${FLEX_FIND_VERSION}")
+      MESSAGE(SEND_ERROR "Your version of flex is too old. You can specify an alternative path using -DFLEX_EXECUTABLE=/path/to/flex")
+    ENDIF()
+  ENDIF()
+
   #============================================================
   # FLEX_TARGET (public macro)
   #============================================================
@@ -176,4 +182,4 @@ INCLUDE(FindPackageHandleStandardArgs)
 FIND_PACKAGE_HANDLE_STANDARD_ARGS(FLEX FLEX_EXECUTABLE
                                        FLEX_VERSION)
 
-# FindFLEX.cmake ends here
\ No newline at end of file
+# FindFLEX.cmake ends here
diff --git a/tools/mkclass/CMakeLists.txt b/tools/mkclass/CMakeLists.txt
index e5beb13b6..a94c6046d 100644
--- a/tools/mkclass/CMakeLists.txt
+++ b/tools/mkclass/CMakeLists.txt
@@ -18,10 +18,6 @@
 find_package(BISON 2.3.0 REQUIRED)
 find_package(FLEX 2.5.31 REQUIRED)
 
-if("${FLEX_VERSION}" VERSION_LESS "2.5.31")
-    message(SEND_ERROR "Your version of flex is too old. You can specify an alternative path using -DFLEX_EXECUTABLE=/path/to/flex")
-endif()
-
 bison_target(class_parser class_parser.yy ${CMAKE_CURRENT_BINARY_DIR}/class_parser.cc)
 flex_target(class_lexer class_lexer.ll ${CMAKE_CURRENT_BINARY_DIR}/class_lexer.cc)
 add_flex_bison_dependency(class_lexer class_parser)