GMP 6.2.0 doesn't build on C89 compilers - Patch attached

[Colin Finck]

Hi all!

We build GMP as part of a GCC build for a build environment and have
just upgraded to GMP 6.2.0.

Unfortunately, this version fails to build using C89 compilers or under
Linux distributions that don't advertise C99 support. In particular, one
of our developers couldn't compile GMP 6.2.0 under Slackware 14.1 (see
https://jira.reactos.org/browse/ROSBE-164).

Fortunately, there is only one file in GMP 6.2.0 making use of C99-style
variable declarations inside a for loop. Patching these out fixes the build.
A corresponding patch is attached.

I'd be glad to see this fixed upstream, so that we don't have to ship a
patched version of GMP.


Best regards,

Colin Finck
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diff -Naur ./gmp/mpn/generic/compute_powtab.c ./gmp-new/mpn/generic/compute_powtab.c
--- ./gmp/mpn/generic/compute_powtab.c	2020-01-17 07:44:49.000000000 -0600
+++ ./gmp-new/mpn/generic/compute_powtab.c	2020-05-01 15:54:26.834552991 -0500
@@ -70,6 +70,7 @@
   mp_limb_t cy;
   long start_idx;
   int c;
+  long pi;
 
   mp_limb_t big_base = mp_bases[base].big_base;
   int chars_per_limb = mp_bases[base].chars_per_limb;
@@ -139,7 +140,7 @@
       start_idx = n_pows - 3;
     }
 
-  for (long pi = start_idx; pi >= 0; pi--)
+  for (/*long*/ pi = start_idx; pi >= 0; pi--)
     {
       t = powtab_mem_ptr;
       powtab_mem_ptr += 2 * n + 2;
@@ -204,6 +205,7 @@
 			int base, const size_t *exptab, size_t n_pows)
 {
   mp_ptr p, t;
+  long pi;
 
   mp_limb_t big_base = mp_bases[base].big_base;
   int chars_per_limb = mp_bases[base].chars_per_limb;
@@ -223,7 +225,7 @@
 
   mp_size_t n = 1;
   mp_size_t shift = 0;
-  for (long pi = n_pows - 1; pi >= 0; pi--)
+  for (/*long*/ pi = n_pows - 1; pi >= 0; pi--)
     {
       t = powtab_mem_ptr;
       powtab_mem_ptr += 2 * n;
@@ -271,7 +273,7 @@
 
   /* Strip any remaining low zero limbs.  */
   pt -= n_pows + 1;
-  for (long pi = n_pows; pi >= 0; pi--)
+  for (/*long*/ pi = n_pows; pi >= 0; pi--)
     {
       mp_ptr t = pt[pi].p;
       mp_size_t shift = pt[pi].shift;
@@ -293,7 +295,9 @@
 {
   int chars_per_limb = mp_bases[base].chars_per_limb;
   long n_pows = 0;
-  for (size_t pn = (un + 1) >> 1; pn != 1; pn = (pn + 1) >> 1)
+  size_t pn;
+  long i;
+  for (/*size_t*/ pn = (un + 1) >> 1; pn != 1; pn = (pn + 1) >> 1)
     {
       exptab[n_pows] = pn * chars_per_limb;
       n_pows++;
@@ -301,11 +305,11 @@
   exptab[n_pows] = chars_per_limb;
 
 #if HAVE_mpn_compute_powtab_mul && HAVE_mpn_compute_powtab_div
-  size_t pn = un - 1;
+  /*size_t*/ pn = un - 1;
   size_t xn = (un + 1) >> 1;
   unsigned mcost = 1;
   unsigned dcost = 1;
-  for (long i = n_pows - 2; i >= 0; i--)
+  for (/*long*/ i = n_pows - 2; i >= 0; i--)
     {
       size_t pow = (pn >> (i + 1)) + 1;
 
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