There's a bit of a mess with the gamma functions. There are _r
versions of these functions that pass through the sign return pointer
instead of applying it locally as they should. That reduces the set of
gamma functions as follows:

Reentrant functions:

        double                  float
        __ieee754_lgamma_r      __ieee754_lgammaf_r
        __ieee754_gamma         __ieee754_gammaf
        
        lgamma_r                lgammaf_r
        tgamma                  tgammaf

gamma/gammaf should be alternate names for tgamma/tgammaf, and would
thus be re-entrant.

Non-reentrant functions:

        __ieee754_lgamma        __ieee754_lgammaf        

        lgamma                  lgammaf

-- 
-keith