I follow the instructions for building clang with MSYS under Windows given on the clang web site.
The 'configure' command runs to completion without any problems.
When I invoke 'make' I get:
'Makefile:139: /Makefile.rules: No such file or directory
make: *** No rule to make target `/Makefile.rules'. Stop.'
In the generated at line 139 I see:
What has gone wrong ?