Cmake build: Next try to use of '--std=c++17' for gnu compiler"

Setting CMAKE_CXX_STANDARD explicitly, so that cmake can use
correct cxx-flags

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 90853559a82efc4eef4b400dd2ec9c247acb8d7a..42b7399c26734969308b4cccbe5cf7bc76bc8e48 100644 (file)
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -692,14 +692,16 @@ else()
        if(NOT LYX_QUIET)
                set(CMAKE_VERBOSE_MAKEFILE ON)
        endif()
-       set(LYX_CXX_FLAGS "-Wall -Wunused-parameter ${LYX_GCC11_MODE}${LYX_CXX_FLAGS}")
-       if(LYX_GCC11_MODE MATCHES "\\+\\+(14|11|98)")
+       if(LYX_GCC11_MODE MATCHES "\\+\\+([0-9][0-9])")
          # Thanks to Brad King <brad.king@kitware.com>
          # for the pointer to https://cmake.org/cmake/help/v3.6/variable/CMAKE_CXX_STANDARD.html
          # This allows us to use QT5.7 with recent g++ (version >= 4.9) compilers
          # and still use our own c++ extension tests
          set(CMAKE_CXX_STANDARD ${CMAKE_MATCH_1})
          message(STATUS "CMAKE_CXX_STANDARD set to ${CMAKE_CXX_STANDARD}")
+         set(LYX_CXX_FLAGS "-Wall -Wunused-parameter ${LYX_CXX_FLAGS}")
+       else()
+         set(LYX_CXX_FLAGS "-Wall -Wunused-parameter ${LYX_GCC11_MODE}${LYX_CXX_FLAGS}")
        endif()
        if(LYX_STDLIB_DEBUG)
          set(LYX_CXX_FLAGS "${LYX_CXX_FLAGS} -D_GLIBCXX_DEBUG -D_GLIBCXX_DEBUG_PEDANTIC")

diff --git a/development/cmake/modules/FindCXX11Compiler.cmake b/development/cmake/modules/FindCXX11Compiler.cmake
index 9188ab6f5b9b50de7ed77a85000add835c299c02..96b72eb33fad6b990afc56ae116a43a399e22f9e 100644 (file)
--- a/development/cmake/modules/FindCXX11Compiler.cmake
+++ b/development/cmake/modules/FindCXX11Compiler.cmake
@@ -54,6 +54,7 @@ else()
       endif()
     else()
       set(CXX11_FLAG_CANDIDATES
+        "--std=c++17"
         "--std=c++14"
         "--std=c++11"
         "--std=gnu++11"