Building QtV8 in debug mode will fail on OSX

When building on OSX and NOT using -release the build will fail building QtV8 with the following error.

clang++ -headerpad_max_install_names -mmacosx-version-min=10.6 -o tst_v8 tst_v8.o v8test.o -F/Users/qt/ttomkins/qt5/qtbase/lib -L/Users/qt/ttomkins/qt5/qtbase/lib -framework QtTest -L/Users/qt/ttomkins/qt5/qtbase/lib -F/Users/qt/ttomkins/qt5/qtbase/lib -framework IOKit -framework Security -framework ApplicationServices -framework QtCore -framework QtV8
ld: framework not found QtV8
clang: error: linker command failed with exit code 1 (use -v to see invocation)
make[3]: *** [tst_v8] Error 1
make[2]: *** [sub-v8-make_default] Error 2
make[1]: *** [sub-auto-make_default] Error 2
make: *** [module-qtjsbackend-tests-make_default] Error 2

The debug platform option is NOT being tested in the CI, hence why this regression could have occured.