QtTest Project with corrupt QT_TESTCASE_BUILDDIR define

Qt projects which use the testlib module cannot be compiled, because of the following compiler error:

error C2664: "void QTest::setMainSourcePath(const char *,const char *)" : Conversion of argument 2 from "int" to "const char *" not possible

This is caused by the following section inside the qtest.h

#ifdef QT_TESTCASE_BUILDDIR
#  define QTEST_SET_MAIN_SOURCE_PATH  QTest::setMainSourcePath(__FILE__, QT_TESTCASE_BUILDDIR);
#else
#  define QTEST_SET_MAIN_SOURCE_PATH  QTest::setMainSourcePath(__FILE__);
#endif

Since the QT_TESTCASE_BUILDDIR is defined by the mkspecs\features\testlib_defines.prf but the RegEx in QMake_DEFINES_ extracts only the key without the value, the above if branch is executed but the define is empty.
To avoid that I've included also the values by using DEFINES=/-D(\S+)/$1/, which extracts correctly, but the value is incompatible with MSVC.

The mentioned testlib_defines.prf contains the following content, but since apparently none of the vc templates is used, the alternative (incompatible) value is set.

contains(TEMPLATE, vc.*): DEFINES += QT_TESTCASE_BUILDDIR=\"$$OUT_PWD\"
else: DEFINES += QT_TESTCASE_BUILDDIR=$$shell_quote(\"$$OUT_PWD\")

As a workaround I've now excluded the define which works at the moment. DEFINES=/-D((?!QT_TESTCASE_BUILDDIR)\S+)/$1/