Depending on from where bison is called, the file might not end up in
the same directory as the .y file, but the location of the Makefile.
This has been seen on FreeBSD.
gperf is not actually a build dependency as the generated files are
shipped in the tarball. So the type depends on the gperf version on
the host that ran gperf and created the tarball, which might not be
the same as that on the actual build host, and gperf might not even
be installed there, leaving the type undetermined.
Fixes: e0e4322973 ("configure: Detect type of length parameter for gperf generated function")
The parser simply returns key/value pairs of all sections, it already
resolves also= and allows overriding options in all included sections
(not only %default), options set in included section can also be cleared
again (key=).
It provides other improvements too, like quoted strings (with escape
sequences), unlimited includes and better whitespace/comment handling.
Tobias Brunner