Try to fix nightly

Author: dantti

.github/workflows/nightly.yml

@@ -20,11 +20,12 @@ jobs:
             cmake_arg: '-DCMAKE_CXX_CLANG_TIDY=clang-tidy'
             qt_version: 6.6
 
-          - name: clazy
-            cmake_arg: '-DCMAKE_CXX_COMPILER=clazy'
-            qt_version: 6.6
-            apt_pgks:
-              - clazy
+          # clazy from ubuntu 24 is based on clang 15 which is too old for this C++ version
+          # - name: clazy
+          #   cmake_arg: '-DCMAKE_CXX_COMPILER=clazy'
+          #   qt_version: 6.4.2
+          #   apt_pgks:
+          #     - clazy
 
     steps:
       - name: Install Qt ${{ matrix.config.qt_version }} with options and default aqtversion

CMakeLists.txt

@@ -37,6 +37,10 @@ set(CMAKE_CXX_STANDARD 20)
 set(CMAKE_CXX_STANDARD_REQUIRED ON)
 set(CMAKE_CXX_EXTENSIONS OFF)
 
+if (CMAKE_CXX_COMPILER_ID MATCHES "Clang")
+    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -stdlib=libc++")
+endif()
+
 # Forbid in-tree building
 if(CMAKE_CURRENT_SOURCE_DIR MATCHES CMAKE_BINARY_DIR)
     message(STATUS "Please do an out-of-tree build:")