logic of config options

[Giuseppe Ghibò]

Hi.

I'm trying to package petsc 2.3.3, but I didn't understand the logic
of some options, in particular for umfpack.  E.g. If I specify at the
config stage:

--with-umfpack-lib=[${_libdir}/libumfpack.a,${_libdir}/libamd.a]

and the ${_libdir} path contains both shared and static libraries then
the linking command are expanded to:

-lumfpack -Wl,-rpath,<path of petsc> -lamd

Ditto if I specify:

--with-umfpack-lib=[libumfpack.a]

they are expanded to the two libs "-lumpack -lamd" (i.e. it guesses the
other lib "libamd" even if I don't specify). So what is the logic behind the --with-xxx-lib
option?  Should I specify just the list of comma separated libraries
enclosed in '[...]' pair? And how to force the usage of static libraries
when both shared and static exists? Because in other cases I see it
could be specified also the linking command. E.g., if I have a
system-wide lapack library, I could use:

--with-lapack-lib=[-llapack]

but this sound working in some option and not in some other. So what
is the "right way"?

Thanks in advance for any help.

Bye
Giuseppe.