guile: removing calls to check for guile and guile-dev. GNU Radio can once again be built without Guile.
More generic error message if guile-dev not installed.
Check for lt_dladvise_global and fall back to using lt_dlopenext if not found.
flag an error if --enable-guile is specified, but guile-dev is not
Add missing -
add variables for the data and lib directories as specified by guile-config
use guile-config to find the proper flags
minimal test for guile flags
add stubs for finding what is needed to use guile or tcl