Patch for grib_api, path handling in autotools

Dear grib_api developers,

first of all, thank you for all the work you did in the last two
releases of grib_api: I have noticed that the patches I was maintaining
have been finally integrated, and packaging 1.10 for Debian has needed
far less effort than it used to. Thank you!

In the past days I have been working at building coinstallable grib_api
packages built with different fortran compilers. It has been relatively
smooth, but in the process I noticed that configure.ac had a nonstandard
way to deal with installation directory variables.

Please find attached a new patch which should simplify handling of data
directories. I admit I did not fully understand the logic of the
original configure.ac code; however, I have tested the patch it in my
system: it installs correctly, grib_info shows the right paths, and
grib_dump is able to dump some test GRIB files.

For context about my patch, see http://www.gnu.org/software/autoconf/manual/autoconf-2.67/html_node/Installation-Directory-Variables.html
at the point where it says "A corollary is that you should not use these
variables except in makefiles."

Best regards,

Enrico

–
GPG key: 4096R/E7AD5568 2009-05-08 Enrico Zini <enrico@enricozini.org>