diff -Naurd mpfr-4.0.2-a/PATCHES mpfr-4.0.2-b/PATCHES
--- mpfr-4.0.2-a/PATCHES	2020-03-30 16:50:17.064231191 +0000
+++ mpfr-4.0.2-b/PATCHES	2020-03-30 16:50:17.096230810 +0000
@@ -0,0 +1 @@
+array-length
diff -Naurd mpfr-4.0.2-a/VERSION mpfr-4.0.2-b/VERSION
--- mpfr-4.0.2-a/VERSION	2020-03-30 15:17:31.535330224 +0000
+++ mpfr-4.0.2-b/VERSION	2020-03-30 16:50:17.096230810 +0000
@@ -1 +1 @@
-4.0.2-p5
+4.0.2-p6
diff -Naurd mpfr-4.0.2-a/src/mpfr-impl.h mpfr-4.0.2-b/src/mpfr-impl.h
--- mpfr-4.0.2-a/src/mpfr-impl.h	2020-03-30 13:09:17.490071686 +0000
+++ mpfr-4.0.2-b/src/mpfr-impl.h	2020-03-30 16:50:17.084230953 +0000
@@ -2026,7 +2026,21 @@
 struct mpfr_group_t {
   size_t     alloc;
   mp_limb_t *mant;
+#if MPFR_GROUP_STATIC_SIZE != 0
   mp_limb_t  tab[MPFR_GROUP_STATIC_SIZE];
+#else
+  /* In order to detect memory leaks when testing, MPFR_GROUP_STATIC_SIZE
+     can be set to 0, in which case tab will not be used. ISO C does not
+     support zero-length arrays[*], thus let's use a flexible array member
+     (which will be equivalent here). Note: this is new in C99, but this
+     is just used for testing.
+     [*] Zero-length arrays are a GNU extension:
+           https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html
+         and as such an extension is forbidden in ISO C, it triggers an
+         error with -Werror=pedantic.
+  */
+  mp_limb_t  tab[];
+#endif
 };
 
 #define MPFR_GROUP_DECL(g) struct mpfr_group_t g
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 15:17:31.535330224 +0000
+++ mpfr-4.0.2-b/src/mpfr.h	2020-03-30 16:50:17.096230810 +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-p5"
+#define MPFR_VERSION_STRING "4.0.2-p6"
 
 /* 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 15:17:31.535330224 +0000
+++ mpfr-4.0.2-b/src/version.c	2020-03-30 16:50:17.096230810 +0000
@@ -25,5 +25,5 @@
 const char *
 mpfr_get_version (void)
 {
-  return "4.0.2-p5";
+  return "4.0.2-p6";
 }