configure.exe ignores failed call of syncqt

Configure.exe usuallay calls the Perl script syncqt. That fails when Perl is not in the path. But the failure is silent and the build continues. Only the failing build of the host tools (included headers not fond) will stop the configuration process. So, the user has to find out the hard way that Perl is missing in the path.

Configure.exe should stop when syncqt fails. Ideally, in that case it would also check if Perl is present and give a proper hint.