Add configure-time checking for the SSE and AVX features on Windows

Modify configure.exe to run some configure-time tests and check if
the SSE and AVX compiler features are supported.

The tests themselves required a bit of changes to compile with
MSVC. The include in sse4_2.cpp was wrong. And for whatever reason, it
didn't like the volatile variables, which GCC, Clang and ICC have been
happy with. This should produce no effect in compilation, though: even
dead code must be syntactically correct. We're not running the output.

Change-Id: Ibe5d0904a378a7efed853c7215f88a2ddcefb1b3
Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@nokia.com>

1 files changed, 6 insertions, 3 deletions

diff --git a/tools/configure/environment.cpp b/tools/configure/environment.cpp
index 43cfc06599..0365340833 100644
--- a/tools/configure/environment.cpp
+++ b/tools/configure/environment.cpp
@@ -431,7 +431,7 @@ int Environment::execute(QStringList arguments, const QStringList &additionalEnv
 
     Taken from qmake's system() command.
 */
-QString Environment::execute(const QString &command)
+QString Environment::execute(const QString &command, int *returnCode)
 {
     QString output;
     FILE *proc = _popen(command.toLatin1().constData(), "r");
@@ -443,8 +443,11 @@ QString Environment::execute(const QString &command)
         buff[read_in] = '\0';
         output += buff;
     }
-    if (proc)
-        _pclose(proc);
+    if (proc) {
+        int r = _pclose(proc);
+        if (returnCode)
+            *returnCode = r;
+    }
     return output;
 }