bug#25786: [PATCH] use of abs() in numbers.c: should be labs()

[Matt Wette]

In libguile/numbers.c abs() is used for long argument where labs() should be used.  

A patch is included below for guile-2.1.7.

/* Returns log(n/d), for exact non-zero integers n and d */

static SCM

log_of_fraction (SCM n, SCM d)

{

  long n_size = scm_to_long (scm_integer_length (n));

  long d_size = scm_to_long (scm_integer_length (d));

  if (abs (n_size - d_size) > 1)

    return (scm_difference (log_of_exact_integer (n),

                            log_of_exact_integer (d)));

--- libguile/numbers.c.orig 2017-02-18 08:29:52.000000000 -0800

+++ libguile/numbers.c 2017-02-18 08:30:23.000000000 -0800

@@ -9951,7 +9951,7 @@

   long n_size = scm_to_long (scm_integer_length (n));

   long d_size = scm_to_long (scm_integer_length (d));

 

-  if (abs (n_size - d_size) > 1)

+  if (labs (n_size - d_size) > 1)

     return (scm_difference (log_of_exact_integer (n),

     log_of_exact_integer (d)));

   else if (scm_is_false (scm_negative_p (n)))