Fix corner case in preprocessor of QOpenGLShaderProgram

The preprocessor used in QOpenGLShaderProgram to help with determining
where it should add the #line and other #define directives is broken
when parsing the standard Qt Project copyright header.

In a multiline comment if the preprocessor encounters repeated '*'
characters when in a multiline comment, it toggles the state between
MultiLineComment and CommentEnding. This is wrong as every asterisk is
potentially the one before the closing '/' of a multiline comment.

This change fixes this by only going back to the MultiLineComment when
in the CommentEnding state if the character is not another '*'.

Task-number: QTBUG-43240
Change-Id: I114e933026ba5de1c23f3e0399613def59f44961
Reviewed-by: Paul Lemire <paul.lemire@kdab.com>

src/gui/opengl/qopenglshaderprogram.cpp

@@ -471,7 +471,8 @@ static QVersionDirectivePosition findVersionDirectivePosition(const char *source
             } else {
                 if (*c == QLatin1Char('#'))
                     *c = QLatin1Char('_');
-                state = MultiLineComment;
+                if (*c != QLatin1Char('*'))
+                    state = MultiLineComment;
             }
             break;
         }