Don't bootstrap QT_EVAL code

For most bootstrapped tools, the QT_EVAL code will not
have any effect, because most of the tools don't instantiate
a QCoreApplication. However, qdoc is bootstrapped for cross
compilation, and will instantiate QCoreApplication which
calls the QT_EVAL code. Since the QT_EVAL code requires QObject,
and QObject requires moc, it does not make sense to compile the
eval code into the bootstrap library. Instead, we simply disable
it to make sure the build succeeds.

Change-Id: I472803572b070df041014d337c23d3f3dc0749e4
Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@digia.com>

src/tools/bootstrap/bootstrap.pro

@@ -28,6 +28,8 @@ DEFINES += \
     QT_CRYPTOGRAPHICHASH_ONLY_SHA1 \
     QT_NO_CAST_FROM_ASCII
 
+DEFINES -= QT_EVAL
+
 MODULE_PRIVATE_INCLUDES = \
     \$\$QT_MODULE_INCLUDE_BASE \
     \$\$QT_MODULE_INCLUDE_BASE/QtCore \