* gnu/packages/guile.scm (guile-gdbm-ffi): Check guile for effective version
before writing to output path. Also fixes a bug where the guild command was
not getting called, and instead was calling the internal guile compile-file
procedure. This meant that the package produced was dependent on whatever
version of guile was powering Guix at the time. Also set GUILE_AUTO_COMPILE
to 0 to avoid gnarly looking warnings during build.