Only use fallback values for the -std= command line option when needed

Instead of always using the fallback value, we instead always use the
standard value unless we know we're running an older toolchain
which does not support it. This alleviates the potential for differing
behavior in newer versions of compilers which may attempt to remain
compatible with earlier drafts of corresponding standards.

[ChangeLog] Always use standard values for -std= when possible

Change-Id: I61ff3ecd863caa24cb8fb54500e62dc310a2af02
Reviewed-by: Jake Petroules <jake.petroules@qt.io>
Reviewed-by: Leena Miettinen <riitta-leena.miettinen@qt.io>
Reviewed-by: Christian Kandeler <christian.kandeler@qt.io>

1 files changed, 7 insertions, 0 deletions

diff --git a/share/qbs/modules/cpp/CppModule.qbs b/share/qbs/modules/cpp/CppModule.qbs
index b4ef22c8d..377b89ede 100644
--- a/share/qbs/modules/cpp/CppModule.qbs
+++ b/share/qbs/modules/cpp/CppModule.qbs
@@ -290,6 +290,13 @@ Module {
         description: "The version of the C++ standard with which the code must comply."
     }
 
+    property bool useLanguageVersionFallback
+    PropertyOptions {
+        name: "useLanguageVersionFallback"
+        description: "whether to explicitly use the language standard version fallback values in " +
+                     "compiler command line invocations"
+    }
+
     property string cxxStandardLibrary
     PropertyOptions {
         name: "cxxStandardLibrary"