[Patch, Fortran] Simplify Bessel_* functions

[FX]

> ... better still is to mark all these arguments with  
> ATTRIBUTE_UNUSED, which should get get bootstrap to build again.  
> Pre-approved if it is verified that if fixes bootstrap.


I've done that, checked that it didn't break bootstrap on x86_64- 
linux when recent MPFR is available, and committed as rev. 134998 to  
fix the breakage ASAP.

FX

-- 
François-Xavier Coudert
http://www.homepages.ucl.ac.uk/~uccafco/