diff --git a/diffutils-sigstksz.patch b/diffutils-sigstksz.patch
new file mode 100644
index 0000000..a632343
--- /dev/null
+++ b/diffutils-sigstksz.patch
@@ -0,0 +1,25 @@
+diff -up diffutils-3.7/lib/c-stack.c.sigstksz diffutils-3.7/lib/c-stack.c
+--- diffutils-3.7/lib/c-stack.c.sigstksz	2021-04-12 10:58:48.892279388 +0100
++++ diffutils-3.7/lib/c-stack.c	2021-04-12 11:04:59.488695551 +0100
+@@ -52,12 +52,18 @@ typedef struct sigaltstack stack_t;
+ #endif
+ #ifndef SIGSTKSZ
+ # define SIGSTKSZ 16384
+-#elif HAVE_LIBSIGSEGV && SIGSTKSZ < 16384
++#elif HAVE_LIBSIGSEGV
+ /* libsigsegv 2.6 through 2.8 have a bug where some architectures use
+    more than the Linux default of an 8k alternate stack when deciding
+    if a fault was caused by stack overflow.  */
+-# undef SIGSTKSZ
+-# define SIGSTKSZ 16384
++# if defined _SC_SIGSTKSZ && _SC_SIGSTKSZ < 16384
++   /* glibc 2.34 defines SIGSTKSZ to sysconf (_SC_SIGSTKSZ) */
++#  undef SIGSTKSZ
++#  define SIGSTKSZ 16384
++# elif SIGSTKSZ < 16384
++#  undef SIGSTKSZ
++#  define SIGSTKSZ 16384
++# endif
+ #endif
+ 
+ #include <stdlib.h>
diff --git a/diffutils.spec b/diffutils.spec
index 6eb2f9b..17a941d 100644
--- a/diffutils.spec
+++ b/diffutils.spec
@@ -7,6 +7,7 @@ Source: https://ftp.gnu.org/gnu/diffutils/diffutils-%{version}.tar.xz
 Patch1: diffutils-cmp-s-empty.patch
 Patch2: diffutils-i18n.patch
 Patch3: diffutils-fix-gnulib-tests.patch
+Patch4: diffutils-sigstksz.patch
 License: GPLv3+
 Provides: bundled(gnulib)
 BuildRequires: gcc
@@ -37,6 +38,9 @@ Install diffutils if you need to compare text files.
 # Fix from gnulib upstream, commit 175e0bc (bug #1863423).
 %patch3 -p1 -b .fix-gnulib-tests
 
+# Handle SIGSTKSZ no longer being a constant (bug #1943016).
+%patch4 -p1 -b .sigstksz
+
 # Run autoreconf for aarch64 support (bug #925256).
 autoreconf
 
@@ -63,6 +67,9 @@ make check
 %{_infodir}/diffutils.info*
 
 %changelog
+* Mon Apr 12 2021 Tim Waugh <twaugh@redhat.com> - 3.7-9
+- Handle SIGSTKSZ no longer being a constant (bug #1943016).
+
 * Tue Jan 26 2021 Fedora Release Engineering <releng@fedoraproject.org> - 3.7-8
 - Rebuilt for https://fedoraproject.org/wiki/Fedora_34_Mass_Rebuild