# Original patch for libmpfr 3.1.2 is here:
# http://www.mpfr.org/mpfr-3.1.2/patch11
# Backported to libmpfr 2.4.2.
--- strtofr.c	2009-11-29 18:43:08.000000000 -0800
+++ strtofr.c	2015-01-23 11:30:29.242406530 -0800
@@ -464,8 +464,10 @@
       /* prec bits corresponds to ysize limbs */
       ysize_bits = ysize * BITS_PER_MP_LIMB;
       /* and to ysize_bits >= prec > MPFR_PREC (x) bits */
-      y = (mp_limb_t*) MPFR_TMP_ALLOC ((2 * ysize + 1) * sizeof (mp_limb_t));
-      y += ysize; /* y has (ysize+1) allocated limbs */
+      /* we need to allocate one more limb to work around
+       * https://gmplib.org/list-archives/gmp-bugs/2013-December/003267.html */
+      y = (mp_limb_t*) MPFR_TMP_ALLOC ((2 * ysize + 2) * sizeof (mp_limb_t));
+      y += ysize; /* y has (ysize+2) allocated limbs */
 
       /* pstr_size is the number of characters we read in pstr->mant
          to have at least ysize full limbs.