[LyX/master] Cmake build: Start demanding at least version 5.1 if compiling with gcc

[Kornel Benko]

commit d6fba3b94e54ac58806d7cb65584edfdbe6d515e
Author: Kornel Benko <kornel at lyx.org>
Date:   Thu Oct 24 14:52:22 2024 +0200

    Cmake build: Start demanding at least version 5.1 if compiling with gcc
---
 CMakeLists.txt | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 54b029b4b2..ac08a2bf56 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -77,9 +77,10 @@ if(NOT help AND NOT HELP)
   # 'project' triggers the searching for a compiler
   project(${LYX_PROJECT})
   if (CMAKE_COMPILER_IS_GNUCXX)
-    if (CMAKE_CXX_COMPILER_VERSION VERSION_LESS "4.9")
+    set(MIN_GCC_VERSION "5.1")
+    if (CMAKE_CXX_COMPILER_VERSION VERSION_LESS ${MIN_GCC_VERSION})
       message(STATUS "Gnu CXX compiler version = ${CMAKE_CXX_COMPILER_VERSION}")
-      message(STATUS "is too old, should be >= 4.9")
+      message(STATUS "is too old, should be >= ${MIN_GCC_VERSION}")
       message(FATAL_ERROR "Exiting")
     endif()
   endif()