diff -Naurd mpfr-4.0.2-a/PATCHES mpfr-4.0.2-b/PATCHES
--- mpfr-4.0.2-a/PATCHES	2020-03-30 16:31:45.813415121 +0000
+++ mpfr-4.0.2-b/PATCHES	2020-03-30 16:33:54.623893528 +0000
@@ -0,0 +1 @@
+const
diff -Naurd mpfr-4.0.2-a/VERSION mpfr-4.0.2-b/VERSION
--- mpfr-4.0.2-a/VERSION	2020-03-30 13:09:17.502071540 +0000
+++ mpfr-4.0.2-b/VERSION	2020-03-30 15:17:31.535330224 +0000
@@ -1 +1 @@
-4.0.2-p4
+4.0.2-p5
diff -Naurd mpfr-4.0.2-a/acinclude.m4 mpfr-4.0.2-b/acinclude.m4
--- mpfr-4.0.2-a/acinclude.m4	2019-01-27 18:30:16.000000000 +0000
+++ mpfr-4.0.2-b/acinclude.m4	2019-01-27 18:30:16.000000000 +0000
@@ -438,12 +438,14 @@
   AC_MSG_WARN([platform and/or document the behavior.])
 fi
 
-dnl Check if the chars '0' to '9' are consecutive values
+dnl Check if the chars '0' to '9', 'a' to 'z', and 'A' to 'Z' are
+dnl consecutive values.
+dnl The const is necessary with GCC's "-Wwrite-strings -Werror".
 AC_MSG_CHECKING([if charset has consecutive values])
 AC_RUN_IFELSE([AC_LANG_PROGRAM([[
-char *number = "0123456789";
-char *lower  = "abcdefghijklmnopqrstuvwxyz";
-char *upper  = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
+const char *number = "0123456789";
+const char *lower  = "abcdefghijklmnopqrstuvwxyz";
+const char *upper  = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
 ]],[[
  int i;
  unsigned char *p;
diff -Naurd mpfr-4.0.2-a/configure mpfr-4.0.2-b/configure
--- mpfr-4.0.2-a/configure	2019-01-31 20:43:19.000000000 +0000
+++ mpfr-4.0.2-b/configure	2020-03-30 16:33:29.340190160 +0000
@@ -15868,9 +15868,9 @@
   cat confdefs.h - <<_ACEOF >conftest.$ac_ext
 /* end confdefs.h.  */
 
-char *number = "0123456789";
-char *lower  = "abcdefghijklmnopqrstuvwxyz";
-char *upper  = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
+const char *number = "0123456789";
+const char *lower  = "abcdefghijklmnopqrstuvwxyz";
+const char *upper  = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
 
 int
 main (void)
diff -Naurd mpfr-4.0.2-a/src/mpfr.h mpfr-4.0.2-b/src/mpfr.h
--- mpfr-4.0.2-a/src/mpfr.h	2020-03-30 13:09:17.498071589 +0000
+++ mpfr-4.0.2-b/src/mpfr.h	2020-03-30 15:17:31.535330224 +0000
@@ -27,7 +27,7 @@
 #define MPFR_VERSION_MAJOR 4
 #define MPFR_VERSION_MINOR 0
 #define MPFR_VERSION_PATCHLEVEL 2
-#define MPFR_VERSION_STRING "4.0.2-p4"
+#define MPFR_VERSION_STRING "4.0.2-p5"
 
 /* User macros:
    MPFR_USE_FILE:        Define it to make MPFR define functions dealing
diff -Naurd mpfr-4.0.2-a/src/version.c mpfr-4.0.2-b/src/version.c
--- mpfr-4.0.2-a/src/version.c	2020-03-30 13:09:17.502071540 +0000
+++ mpfr-4.0.2-b/src/version.c	2020-03-30 15:17:31.535330224 +0000
@@ -25,5 +25,5 @@
 const char *
 mpfr_get_version (void)
 {
-  return "4.0.2-p4";
+  return "4.0.2-p5";
 }
diff -Naurd mpfr-4.0.2-a/tests/tdiv.c mpfr-4.0.2-b/tests/tdiv.c
--- mpfr-4.0.2-a/tests/tdiv.c	2019-01-07 13:53:20.000000000 +0000
+++ mpfr-4.0.2-b/tests/tdiv.c	2020-03-30 15:17:31.523330366 +0000
@@ -23,7 +23,7 @@
 #include "mpfr-test.h"
 
 static void
-check_equal (mpfr_srcptr a, mpfr_srcptr a2, char *s,
+check_equal (mpfr_srcptr a, mpfr_srcptr a2, const char *s,
              mpfr_srcptr b, mpfr_srcptr c, mpfr_rnd_t r)
 {
   if (SAME_VAL (a, a2))
diff -Naurd mpfr-4.0.2-a/tests/tfpif.c mpfr-4.0.2-b/tests/tfpif.c
--- mpfr-4.0.2-a/tests/tfpif.c	2019-01-07 13:53:20.000000000 +0000
+++ mpfr-4.0.2-b/tests/tfpif.c	2020-03-30 15:17:31.523330366 +0000
@@ -30,8 +30,8 @@
 static void
 doit (int argc, char *argv[], mpfr_prec_t p1, mpfr_prec_t p2)
 {
-  char *filenameCompressed = FILE_NAME_RW;
-  char *data = FILE_NAME_R;
+  const char *filenameCompressed = FILE_NAME_RW;
+  const char *data = FILE_NAME_R;
   int status;
   FILE *fh;
   mpfr_t x[9];
@@ -198,7 +198,7 @@
 static void
 check_bad (void)
 {
-  char *filenameCompressed = FILE_NAME_RW;
+  const char *filenameCompressed = FILE_NAME_RW;
   int status;
   FILE *fh;
   mpfr_t x;
@@ -340,7 +340,7 @@
 static void
 extra (void)
 {
-  char *data = FILE_NAME_R2;
+  const char *data = FILE_NAME_R2;
   mpfr_t x;
   FILE *fp;
   int ret;
diff -Naurd mpfr-4.0.2-a/tests/tmul_2exp.c mpfr-4.0.2-b/tests/tmul_2exp.c
--- mpfr-4.0.2-a/tests/tmul_2exp.c	2019-01-07 13:53:20.000000000 +0000
+++ mpfr-4.0.2-b/tests/tmul_2exp.c	2020-03-30 15:17:31.523330366 +0000
@@ -258,7 +258,7 @@
   mpfr_exp_t old_emax;
   mpfr_t x, y1, y2;
   int neg, r, op;
-  static char *sop[4] = { "mul_2ui", "mul_2si", "div_2ui", "div_2si" };
+  static const char *sop[4] = { "mul_2ui", "mul_2si", "div_2ui", "div_2si" };
 
   old_emax = mpfr_get_emax ();
   set_emax (emax);
diff -Naurd mpfr-4.0.2-a/tests/trandom.c mpfr-4.0.2-b/tests/trandom.c
--- mpfr-4.0.2-a/tests/trandom.c	2019-01-07 13:53:20.000000000 +0000
+++ mpfr-4.0.2-b/tests/trandom.c	2020-03-30 15:17:31.523330366 +0000
@@ -185,7 +185,7 @@
   {
     gmp_randstate_t s;
     mpfr_t x;
-    char *str = "0.1010111100000000000000000000000000000000E-32";
+    const char *str = "0.1010111100000000000000000000000000000000E-32";
     int k;
 
     gmp_randinit_default (s);
diff -Naurd mpfr-4.0.2-a/tests/trint.c mpfr-4.0.2-b/tests/trint.c
--- mpfr-4.0.2-a/tests/trint.c	2019-01-25 02:00:06.000000000 +0000
+++ mpfr-4.0.2-b/tests/trint.c	2020-03-30 15:17:31.523330366 +0000
@@ -308,7 +308,7 @@
 #if __MPFR_STDC (199901L)
 
 static void
-test_fct (double (*f)(double), int (*g)(), char *s, mpfr_rnd_t r)
+test_fct (double (*f)(double), int (*g)(), const char *s, mpfr_rnd_t r)
 {
   double d, y;
   mpfr_t dd, yy;
diff -Naurd mpfr-4.0.2-a/tests/tsum.c mpfr-4.0.2-b/tests/tsum.c
--- mpfr-4.0.2-a/tests/tsum.c	2019-01-07 13:53:20.000000000 +0000
+++ mpfr-4.0.2-b/tests/tsum.c	2020-03-30 15:17:31.523330366 +0000
@@ -285,7 +285,7 @@
 static void
 check_more_special (void)
 {
-  char *str[NC] = { "NaN", "+Inf", "-Inf", "+0", "-0", "+1", "-1" };
+  const char *str[NC] = { "NaN", "+Inf", "-Inf", "+0", "-0", "+1", "-1" };
   int i, r, k[NS];
   mpfr_t c[NC], s[NS], sum;
   mpfr_ptr p[NS];
@@ -724,7 +724,7 @@
 {
   mpfr_t sum, t[4];
   mpfr_ptr p[4];
-  char *s[4] = {
+  const char *s[4] = {
     "0x1p1000",
     "-0x0.fffffffffffff80000000000000001p1000",
     "-0x1p947",
@@ -771,7 +771,11 @@
 {
   mpfr_t sum1, sum2, t[3];
   mpfr_ptr p[3];
-  char *s[3] = { "0.10000111110101000010101011100001", "1E-100", "0.1E95" };
+  const char *s[3] = {
+    "0.10000111110101000010101011100001",
+    "1E-100",
+    "0.1E95"
+  };
   int i, r;
 
   mpfr_inits2 (58, sum1, sum2, (mpfr_ptr) 0);
@@ -1268,7 +1272,7 @@
 {
   mpfr_t r, t[4];
   mpfr_ptr p[4];
-  char *s[4] = { "0.10E20", "0", "0.11E382", "0.10E826" };
+  const char *s[4] = { "0.10E20", "0", "0.11E382", "0.10E826" };
   int i;
 
   mpfr_init2 (r, 2);
diff -Naurd mpfr-4.0.2-a/tests/turandom.c mpfr-4.0.2-b/tests/turandom.c
--- mpfr-4.0.2-a/tests/turandom.c	2019-01-07 13:53:20.000000000 +0000
+++ mpfr-4.0.2-b/tests/turandom.c	2020-03-30 15:17:31.523330366 +0000
@@ -526,7 +526,7 @@
 #define N 6
   /* Run this program with the MPFR_REPROD_ABI_OUTPUT environment variable
      set to get the array of strings. */
-  char *t[5 * N] = {
+  const char *t[5 * N] = {
     "1.0@-1",
     "3.0@-1",
     "7.0@-1",