Support XKB_CONTEXT_NO_SECURE_GETENV flag

Since kwin play with CAP_SYS_NICE, secure_getenv will fail for xkbcommon
to load user level xkbmap. This allows kwin to load config under
~/.config/xkb

BUG: 447206

CMakeLists.txt

@@ -223,6 +223,11 @@ set_package_properties(XKB PROPERTIES
     TYPE REQUIRED
     PURPOSE "Required for building KWin with Wayland support"
 )
+if (XKB_VERSION VERSION_GREATER_EQUAL 1.5.0)
+    set(HAVE_XKBCOMMON_NO_SECURE_GETENV 1)
+else()
+    set(HAVE_XKBCOMMON_NO_SECURE_GETENV 0)
+endif()
 
 pkg_check_modules(XKBX11 IMPORTED_TARGET xkbcommon-x11 REQUIRED)
 add_feature_info(XKBX11 XKBX11_FOUND "Required for handling keyboard events in X11 backend")

src/config-kwin.h.cmake

@@ -19,6 +19,7 @@
 #cmakedefine01 HAVE_BREEZE_DECO
 #cmakedefine01 HAVE_SCHED_RESET_ON_FORK
 #cmakedefine01 HAVE_ACCESSIBILITY
+#cmakedefine01 HAVE_XKBCOMMON_NO_SECURE_GETENV
 #if HAVE_BREEZE_DECO
 #define BREEZE_KDECORATION_PLUGIN_ID "${BREEZE_KDECORATION_PLUGIN_ID}"
 #endif

src/xkb.cpp

@@ -70,8 +70,14 @@ static void xkbLogHandler(xkb_context *context, xkb_log_level priority, const ch
     }
 }
 
+#if HAVE_XKBCOMMON_NO_SECURE_GETENV
+constexpr xkb_context_flags KWIN_XKB_CONTEXT_FLAGS = XKB_CONTEXT_NO_SECURE_GETENV;
+#else
+constexpr xkb_context_flags KWIN_XKB_CONTEXT_FLAGS = XKB_CONTEXT_NO_FLAGS;
+#endif
+
 Xkb::Xkb(bool followLocale1)
-    : m_context(xkb_context_new(XKB_CONTEXT_NO_FLAGS))
+    : m_context(xkb_context_new(KWIN_XKB_CONTEXT_FLAGS))
     , m_keymap(nullptr)
     , m_state(nullptr)
     , m_shiftModifier(0)