[bug-gnuastro] error with compiling interpolate.c

[ichikawa Takashi]

Mohammad,

When installing the newest gnuastro-0.6, "make -j8 " has stopped
at compiling interpolate.c with the following error.

> interpolate.c: In function ‘gal_interpolate_1d_make_gsl_spline’:
> interpolate.c:515:13: error: ‘gsl_interp_steffen’ undeclared (first use in this 
> function)
>        itype=gsl_interp_steffen;          break;
>              ^
> interpolate.c:515:13: note: each undeclared identifier is reported only once 
> for each function it appears in

Such error was not seen in installing older version
(e.g., 0.5.132-60d5), in which gsl_interp_steffen was not
used. gsl_interp_steffen must be appeared first time
in the new version without the definition.

Ichikawa