how to judge repository is an external repo or not in BUILD file?

[xiedeacc]

Description of the feature request:

I'm writing a BUILD file for libdwarf, a genrule used to generate a config.h, and this config.h was included by a source file use

#include <config.h>

this means, directory that contains config.h must be add to search path by -isystem, but bazel just add directory contains config.h use -iquote, so compile will fail for cannot find config.h. so I pass

"-isystem $(GENDIR)/src"

to copts, this works well in libdwarf repository, but if libdwarf is an external repository in other repository, this will compile failed for $(GENDIR)/src not diretory contains config.h any more

here is a demo
https://github.com/xiedeacc/libdwarf.git

bazel 6.2.1