Line numbers for scm_c_primitive_load() errors

[Robert Gill]

I'm trying to read a file with scm_c_primitive_load() that uses some
custom functions defined with scm_c_define_gsubr(). If I pass an invalid
data type to one of these functions, I get an expected exception, but
the line number of the file where they occur is not included in the
stack trace. I tried following the directions in the manual under
'6.25.3.2 Capturing the full error stack', and wrapping the call in
scm_c_catch(), while manually capturing the stack, but it still doesn't
seem to include the line number.

I'm using guile 2.0.14.