From a47cb146809e32f43449dcfe9932833c2f0ab987 Mon Sep 17 00:00:00 2001
From: Allan Sandfeld Jensen <allan.jensen@qt.io>
Date: Wed, 14 Feb 2018 13:40:57 +0100
Subject: Detect C standard and try using the most recent

Fixes the default C version used with gcc < 5

Change-Id: I948dece961caed8e6b181e1c6e6b9dc43c46583f
Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@qt.io>
---
 configure.json | 48 ++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 48 insertions(+)

(limited to 'configure.json')

diff --git a/configure.json b/configure.json
index ae2aa22070..b4d763116c 100644
--- a/configure.json
+++ b/configure.json
@@ -259,6 +259,36 @@
             "type": "compile",
             "test": "stl"
         },
+        "c99": {
+            "label": "C99 support",
+            "type": "compile",
+            "test": {
+                "head": [
+                    "#if __STDC_VERSION__ >= 199901L",
+                    "// Compiler claims to support C99, trust it",
+                    "#else",
+                    "#  error __STDC_VERSION__ must be >= 199901L",
+                    "#endif"
+                ],
+                "lang": "c",
+                "qmake": "CONFIG += c99"
+            }
+        },
+        "c11": {
+            "label": "C11 support",
+            "type": "compile",
+            "test": {
+                "head": [
+                    "#if __STDC_VERSION__ >= 201112L",
+                    "// Compiler claims to support C11, trust it",
+                    "#else",
+                    "#  error __STDC_VERSION__ must be >= 201112L",
+                    "#endif"
+                ],
+                "lang": "c",
+                "qmake": "CONFIG += c11"
+            }
+        },
         "c++14": {
             "label": "C++14 support",
             "type": "compile",
@@ -786,6 +816,19 @@
             "condition": "features.c++14 && tests.c++1z",
             "output": [ "publicFeature", "publicQtConfig" ]
         },
+        "c89": {
+            "label": "C89"
+        },
+        "c99": {
+            "label": "C99",
+            "condition": "tests.c99",
+            "output": [ "publicFeature" ]
+        },
+        "c11": {
+            "label": "C11",
+            "condition": "features.c99 && tests.c11",
+            "output": [ "publicFeature" ]
+        },
         "precompile_header": {
             "label": "Using precompiled headers",
             "condition": "config.msvc || tests.precompile_header",
@@ -1246,6 +1289,11 @@ Configure with '-qreal float' to create a build that is binary-compatible with 5
                     "condition": "!features.debug || features.debug_and_release"
                 },
                 "shared",
+                {
+                    "message": "Using C standard",
+                    "type": "firstAvailableFeature",
+                    "args": "c11 c99 c89"
+                },
                 {
                     "message": "Using C++ standard",
                     "type": "firstAvailableFeature",
-- 
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