maint: use Gnulib libgmp module

This lets use assume multiple-precision arithmetic on all
platforms, simplifying the code.
* bootstrap.conf (gnulib_modules): Add libgmp.
* configure.ac: Don’t call cu_GMP, as this is now done by Gnulib.
* m4/gmp.m4: Remove.
* src/expr.c, src/factor.c: Use gmp.h unconditionally.
* src/factor.c: Use the simpler ‘#ifndef mpz_inits’ to
determine whether there is an mpz_inits macro.

bootstrap.conf

@@ -144,6 +144,7 @@ gnulib_modules="
   lchown
   ldtoastr
   lib-ignore
+  libgmp
   linebuffer
   link
   link-follow

configure.ac

@@ -474,8 +474,6 @@ AC_CHECK_DECLS([strsignal, sys_siglist, _sys_siglist, __sys_siglist], , ,
   [AC_INCLUDES_DEFAULT
 #include <signal.h>])
 
-cu_GMP
-
 # Build df only if there's a point to it.
 if test $gl_cv_list_mounted_fs = yes && test $gl_cv_fs_space = yes; then
   gl_ADD_PROG([optional_bin_progs], [df])

m4/gmp.m4

@@ -1,48 +0,0 @@
-# Tests for GNU GMP (or any compatible replacement).
-
-dnl Copyright (C) 2008-2020 Free Software Foundation, Inc.
-
-dnl This file is free software; the Free Software Foundation
-dnl gives unlimited permission to copy and/or distribute it,
-dnl with or without modifications, as long as this notice is preserved.
-
-dnl Written by James Youngman.
-
-dnl Check for libgmp.  We avoid use of AC_CHECK_LIBS because we don't want to
-dnl add this to $LIBS for all targets.
-AC_DEFUN([cu_GMP],
-[
-  LIB_GMP=
-  AC_SUBST([LIB_GMP])
-
-  AC_ARG_WITH([gmp],
-    AS_HELP_STRING([--without-gmp],
-      [do not use the GNU MP library for arbitrary precision
-       calculation (default: use it if available)]),
-    [cu_use_gmp=$withval],
-    [cu_use_gmp=auto])
-
-  if test $cu_use_gmp != no; then
-    dnl It was noticed on one MacOS X 10.5.8 system at least
-    dnl that the libs were available but the header wasn't
-    HAVE_GMP=0
-    AC_CHECK_HEADERS_ONCE([gmp.h])
-    if test $ac_cv_header_gmp_h = yes; then
-      cu_saved_libs=$LIBS
-      AC_SEARCH_LIBS([__gmpz_init], [gmp],
-        [test "$ac_cv_search___gmpz_init" = "none required" ||
-           LIB_GMP=$ac_cv_search___gmpz_init
-         AC_DEFINE([HAVE_GMP], [1],
-           [Define if you have GNU libgmp (or replacement)])
-         HAVE_GMP=1
-         # This only available in GMP >= 5
-         AC_CHECK_DECLS([mpz_inits], [], [], [[#include <gmp.h>]])
-        ])
-      LIBS=$cu_saved_libs
-    fi
-    if test $HAVE_GMP != 1; then
-     AC_MSG_WARN([libgmp development library was not found or not usable.])
-     AC_MSG_WARN([AC_PACKAGE_NAME will be built without GMP support.])
-    fi
-  fi
-])

src/expr.c

@@ -33,6 +33,7 @@
 #include <sys/types.h>
 #include "system.h"
 
+#include <gmp.h>
 #include <regex.h>
 #include "die.h"
 #include "error.h"
@@ -45,105 +46,6 @@
    int, the widest unsigned type that GMP supports.  */
 verify (SIZE_MAX <= ULONG_MAX);
 
-#ifndef HAVE_GMP
-# define HAVE_GMP 0
-#endif
-
-#if HAVE_GMP
-# include <gmp.h>
-#else
-static void integer_overflow (char) ATTRIBUTE_NORETURN;
-/* Approximate gmp.h well enough for expr.c's purposes.  */
-typedef intmax_t mpz_t[1];
-static void mpz_clear (mpz_t z) { (void) z; }
-static void mpz_init_set_ui (mpz_t z, unsigned long int i) { z[0] = i; }
-static int
-mpz_init_set_str (mpz_t z, char *s, int base)
-{
-  return xstrtoimax (s, NULL, base, z, "") == LONGINT_OK ? 0 : -1;
-}
-static void
-mpz_add (mpz_t r, mpz_t a0, mpz_t b0)
-{
-  intmax_t a = a0[0];
-  intmax_t b = b0[0];
-  intmax_t val = a + b;
-  if ((val < a) != (b < 0))
-    integer_overflow ('+');
-  r[0] = val;
-}
-static void
-mpz_sub (mpz_t r, mpz_t a0, mpz_t b0)
-{
-  intmax_t a = a0[0];
-  intmax_t b = b0[0];
-  intmax_t val = a - b;
-  if ((a < val) != (b < 0))
-    integer_overflow ('-');
-  r[0] = val;
-}
-static void
-mpz_mul (mpz_t r, mpz_t a0, mpz_t b0)
-{
-  intmax_t a = a0[0];
-  intmax_t b = b0[0];
-  intmax_t val = a * b;
-  if (! (a == 0 || b == 0
-         || ((val < 0) == ((a < 0) ^ (b < 0)) && val / a == b)))
-    integer_overflow ('*');
-  r[0] = val;
-}
-static void
-mpz_tdiv_q (mpz_t r, mpz_t a0, mpz_t b0)
-{
-  intmax_t a = a0[0];
-  intmax_t b = b0[0];
-
-  /* Some x86-style hosts raise an exception for INT_MIN / -1.  */
-  if (a < - INTMAX_MAX && b == -1)
-    integer_overflow ('/');
-  r[0] = a / b;
-}
-static void
-mpz_tdiv_r (mpz_t r, mpz_t a0, mpz_t b0)
-{
-  intmax_t a = a0[0];
-  intmax_t b = b0[0];
-
-  /* Some x86-style hosts raise an exception for INT_MIN % -1.  */
-  r[0] = a < - INTMAX_MAX && b == -1 ? 0 : a % b;
-}
-static char * _GL_ATTRIBUTE_MALLOC
-mpz_get_str (char const *str, int base, mpz_t z)
-{
-  (void) str; (void) base;
-  char buf[INT_BUFSIZE_BOUND (intmax_t)];
-  return xstrdup (imaxtostr (z[0], buf));
-}
-static int
-mpz_sgn (mpz_t z)
-{
-  return z[0] < 0 ? -1 : 0 < z[0];
-}
-static int
-mpz_fits_ulong_p (mpz_t z)
-{
-  return 0 <= z[0] && z[0] <= ULONG_MAX;
-}
-static unsigned long int
-mpz_get_ui (mpz_t z)
-{
-  return z[0];
-}
-static int
-mpz_out_str (FILE *stream, int base, mpz_t z)
-{
-  (void) base;
-  char buf[INT_BUFSIZE_BOUND (intmax_t)];
-  return fputs (imaxtostr (z[0], buf), stream) != EOF;
-}
-#endif
-
 /* The official name of this program (e.g., no 'g' prefix).  */
 #define PROGRAM_NAME "expr"
 
@@ -414,15 +316,6 @@ or 0, 2 if EXPRESSION is syntactically invalid, and 3 if an error occurred.\n\
 }
 
 
-#if ! HAVE_GMP
-/* Report an integer overflow for operation OP and exit.  */
-static void
-integer_overflow (char op)
-{
-  die (EXPR_FAILURE, ERANGE, "%c", op);
-}
-#endif
-
 int
 main (int argc, char **argv)
 {
@@ -603,7 +496,7 @@ toarith (VALUE *v)
 
         if (! looks_like_integer (s))
           return false;
-        if (mpz_init_set_str (v->u.i, s, 10) != 0 && !HAVE_GMP)
+        if (mpz_init_set_str (v->u.i, s, 10) != 0)
           die (EXPR_FAILURE, ERANGE, "%s", (s));
         free (s);
         v->type = integer;

src/factor.c

@@ -35,12 +35,6 @@
     The factoring code for two words will fall into the code for one word when
     progress allows that.
 
-    Using GMP is optional.  Define HAVE_GMP to make this code include GMP
-    factoring code.  The GMP factoring code is based on GMP's demos/factorize.c
-    (last synced 2012-09-07).  The GMP-based factoring code will stay in GMP
-    factoring code even if numbers get small enough for using the two-word
-    code.
-
   Algorithm:
 
     (1) Perform trial division using a small primes table, but without hardware
@@ -104,13 +98,7 @@
 #include <config.h>
 #include <getopt.h>
 #include <stdio.h>
-#if HAVE_GMP
-# include <gmp.h>
-# if !HAVE_DECL_MPZ_INITS
-#  include <stdarg.h>
-# endif
-#endif
-
+#include <gmp.h>
 #include <assert.h>
 
 #include "system.h"
@@ -246,14 +234,12 @@ struct factors
   unsigned char nfactors;
 };
 
-#if HAVE_GMP
 struct mp_factors
 {
   mpz_t             *p;
   unsigned long int *e;
   unsigned long int nfactors;
 };
-#endif
 
 static void factor (uintmax_t, uintmax_t, struct factors *);
 
@@ -570,12 +556,12 @@ factor_insert_large (struct factors *factors,
     factor_insert (factors, p0);
 }
 
-#if HAVE_GMP
+#ifndef mpz_inits
 
-# if !HAVE_DECL_MPZ_INITS
+# include <stdarg.h>
 
-#  define mpz_inits(...) mpz_va_init (mpz_init, __VA_ARGS__)
-#  define mpz_clears(...) mpz_va_init (mpz_clear, __VA_ARGS__)
+# define mpz_inits(...) mpz_va_init (mpz_init, __VA_ARGS__)
+# define mpz_clears(...) mpz_va_init (mpz_clear, __VA_ARGS__)
 
 static void
 mpz_va_init (void (*mpz_single_init)(mpz_t), ...)
@@ -590,7 +576,7 @@ mpz_va_init (void (*mpz_single_init)(mpz_t), ...)
 
   va_end (ap);
 }
-# endif
+#endif
 
 static void mp_factor (mpz_t, struct mp_factors *);
 
@@ -660,7 +646,6 @@ mp_factor_insert_ui (struct mp_factors *factors, unsigned long int prime)
   mp_factor_insert (factors, pz);
   mpz_clear (pz);
 }
-#endif /* HAVE_GMP */
 
 
 /* Number of bits in an uintmax_t.  */
@@ -835,7 +820,6 @@ factor_using_division (uintmax_t *t1p, uintmax_t t1, uintmax_t t0,
   return t0;
 }
 
-#if HAVE_GMP
 static void
 mp_factor_using_division (mpz_t t, struct mp_factors *factors)
 {
@@ -872,7 +856,6 @@ mp_factor_using_division (mpz_t t, struct mp_factors *factors)
 
   mpz_clear (q);
 }
-#endif
 
 /* Entry i contains (2i+1)^(-1) mod 2^8.  */
 static const unsigned char  binvert_table[128] =
@@ -1171,7 +1154,6 @@ millerrabin2 (const uintmax_t *np, uintmax_t ni, const uintmax_t *bp,
   return false;
 }
 
-#if HAVE_GMP
 static bool
 mp_millerrabin (mpz_srcptr n, mpz_srcptr nm1, mpz_ptr x, mpz_ptr y,
                 mpz_srcptr q, unsigned long int k)
@@ -1191,7 +1173,6 @@ mp_millerrabin (mpz_srcptr n, mpz_srcptr nm1, mpz_ptr x, mpz_ptr y,
     }
   return false;
 }
-#endif
 
 /* Lucas' prime test.  The number of iterations vary greatly, up to a few dozen
    have been observed.  The average seem to be about 2.  */
@@ -1377,7 +1358,6 @@ prime2_p (uintmax_t n1, uintmax_t n0)
   abort ();
 }
 
-#if HAVE_GMP
 static bool
 mp_prime_p (mpz_t n)
 {
@@ -1460,7 +1440,6 @@ mp_prime_p (mpz_t n)
 
   return is_prime;
 }
-#endif
 
 static void
 factor_using_pollard_rho (uintmax_t n, unsigned long int a,
@@ -1669,7 +1648,6 @@ factor_using_pollard_rho2 (uintmax_t n1, uintmax_t n0, unsigned long int a,
     }
 }
 
-#if HAVE_GMP
 static void
 mp_factor_using_pollard_rho (mpz_t n, unsigned long int a,
                              struct mp_factors *factors)
@@ -1761,7 +1739,6 @@ mp_factor_using_pollard_rho (mpz_t n, unsigned long int a,
 
   mpz_clears (P, t2, t, z, x, y, NULL);
 }
-#endif
 
 #if USE_SQUFOF
 /* FIXME: Maybe better to use an iteration converging to 1/sqrt(n)?  If
@@ -2251,7 +2228,6 @@ factor (uintmax_t t1, uintmax_t t0, struct factors *factors)
     }
 }
 
-#if HAVE_GMP
 /* Use Pollard-rho to compute the prime factors of
    arbitrary-precision T, and put the results in FACTORS.  */
 static void
@@ -2273,7 +2249,6 @@ mp_factor (mpz_t t, struct mp_factors *factors)
         }
     }
 }
-#endif
 
 static strtol_error
 strto2uintmax (uintmax_t *hip, uintmax_t *lop, const char *s)
@@ -2526,7 +2501,6 @@ print_factors (const char *input)
       return false;
     }
 
-#if HAVE_GMP
   devmsg ("[using arbitrary-precision arithmetic] ");
   mpz_t t;
   struct mp_factors factors;
@@ -2545,10 +2519,6 @@ print_factors (const char *input)
   putchar ('\n');
   fflush (stdout);
   return true;
-#else
-  error (0, 0, _("%s is too large"), quote (input));
-  return false;
-#endif
 }
 
 void