Update for new Clang errors

QGCCommon.pri

@@ -167,6 +167,10 @@ MacBuild | LinuxBuild {
     WarningsAsErrorsOn {
         QMAKE_CXXFLAGS_WARN_ON += -Werror
     }
+    MacBuild {
+        # Latest clang version has a buggy check for this which cause Qt headers to throw warnings on qmap.h
+        QMAKE_CXXFLAGS_WARN_ON += -Wno-return-stack-address
+    }
 }
 
 WindowsBuild {

src/QGCFileDialog.h

@@ -134,7 +134,7 @@ public:
 private slots:
     /// @brief The exec slot is private because we only want QGCFileDialog users to use the static methods. Otherwise it will break
     ///        unit testing.
-    int exec(void) { return QGCFileDialog::exec(); }
+    int exec(void) { return QFileDialog::exec(); }
     
 private:
     static void    _validate(Options& options);

src/ui/QGCDataPlot2D.cc

@@ -644,8 +644,8 @@ bool QGCDataPlot2D::calculateRegression(QString xName, QString yName, QString me
             function = tr("Regression method %1 not found").arg(method);
         }
 
-        delete x;
-        delete y;
+        delete[] x;
+        delete[] y;
     } else {
         // xName == yName
         function = tr("Please select different X and Y dimensions, not %1 = %2").arg(xName, yName);