Update CMake for minimum GCC version: 4.9

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 808a0ccb6e6bd45779c42ead5442a952919c69cf..b35f2f5f8bb37ab1eba31f767bdf878b2f649322 100644 (file)
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -77,9 +77,9 @@ 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 "4.0")
+    if (CMAKE_CXX_COMPILER_VERSION VERSION_LESS "4.9")
       message(STATUS "Gnu CXX compiler version = ${CMAKE_CXX_COMPILER_VERSION}")
-      message(STATUS "is too old, should be >= 4.0")
+      message(STATUS "is too old, should be >= 4.9")
       message(FATAL_ERROR "Exiting")
     endif()
   endif()
@@ -396,25 +396,18 @@ if(UNIX OR MINGW)
            #message(STATUS "dumpversion: error = ${_error}, result = ${_err}")
          endif()
          message(STATUS "Using GCC version ${GCC_VERSION}")
-         if(GCC_VERSION VERSION_LESS 4.6)
-               message(FATAL_ERROR "gcc >= 4.6 is required.")
-         elseif(GCC_VERSION VERSION_LESS 4.9)
-               # <regex> in gcc is unusable in versions less than 4.9.0
-               # see https://gcc.gnu.org/bugzilla/show_bug.cgi?id=53631
-               set(LYX_USE_STD_REGEX 0)
-         else()
-               set(LYX_USE_STD_REGEX 1)
+         if(GCC_VERSION VERSION_LESS 4.9)
+               message(FATAL_ERROR "gcc >= 4.9 is required.")
          endif()
+         set(LYX_USE_STD_REGEX 1)
        endif()
        set(LYX_GCC11_MODE "${CXX11_FLAG}")
 else()
        if(MSVC_VERSION LESS 1900)
                # Drop support for msvc versions prior to 1900 (Visual Studio 2015)
                message(FATAL_ERROR "Visual Studio >= 2015 is required.")
-               set(LYX_USE_STD_REGEX 0)
-       else()
-               set(LYX_USE_STD_REGEX 1)
        endif()
+       set(LYX_USE_STD_REGEX 1)
 endif()
 
 if(LYX_3RDPARTY_BUILD)