File mpfr421.patch of Package python-gmpy2

From 68a6b489c3d8d95b2658a1ed884fb99f4bd955c1 Mon Sep 17 00:00:00 2001
From: Sergey B Kirpichev <skirpichev@gmail.com>
Date: Sun, 3 Sep 2023 02:35:19 +0300
Subject: [PATCH 2/2] Exclude MPFR workaround for MPFR >= 4.2.1

Co-authored-by: Vincent Lefevre <vincent@vinc17.net>

Closes #418
---
 src/gmpy2_format.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/src/gmpy2_format.c b/src/gmpy2_format.c
index 3e450c96..303bb7bf 100644
--- a/src/gmpy2_format.c
+++ b/src/gmpy2_format.c
@@ -592,12 +592,14 @@ GMPy_MPC_Format(PyObject *self, PyObject *args)
     if (mpcstyle)
         strcat(tempbuf, " ");
     else {
+#if MPFR_VERSION < MPFR_VERSION_NUM(4,2,1)
         /* Need to insert + if imag is nan or +inf. */
         if (mpfr_nan_p(mpc_imagref(MPC(self))) ||
             (mpfr_inf_p(mpc_imagref(MPC(self))) &&
              mpfr_sgn(mpc_imagref(MPC(self))) > 0)) {
             strcat(tempbuf, "+");
         }
+#endif
     }
     strcat(tempbuf, imagbuf);
     if (strlen(imagbuf) < 50 &&