The next patch would create the file sysdeps/unix/sysv/linux/sparc/brk.c,
which already exists!  Applying it anyway.
patching file sysdeps/unix/sysv/linux/sparc/brk.c
Hunk #1 FAILED at 1.
1 out of 1 hunk FAILED -- saving rejects to file sysdeps/unix/sysv/linux/sparc/brk.c.rej

Reject file sysdeps/unix/sysv/linux/sparc/brk.c.rej:
--- sysdeps/unix/sysv/linux/sparc/brk.c
+++ sysdeps/unix/sysv/linux/sparc/brk.c
@@ -0,0 +1,58 @@
+/* Change data segment.  Linux SPARC version.
+   Copyright (C) 2021 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library.  If not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#include <errno.h>
+#include <unistd.h>
+#include <sysdep.h>
+
+/* This must be initialized data because commons can't have aliases.  */
+void *__curbrk = 0;
+
+#if HAVE_INTERNAL_BRK_ADDR_SYMBOL
+/* Old braindamage in GCC's crtstuff.c requires this symbol in an attempt
+   to work around different old braindamage in the old Linux ELF dynamic
+   linker.  */
+weak_alias (__curbrk, ___brk_addr)
+#endif
+
+#ifdef __arch64__
+# define SYSCALL_NUM "0x6d"
+#else
+# define SYSCALL_NUM "0x10"
+#endif
+
+int
+__brk (void *addr)
+{
+  register long int g1 asm ("g1") = __NR_brk;
+  register long int o0 asm ("o0") = (long int) addr;
+  asm volatile ("ta " SYSCALL_NUM
+		: "=r"(o0)
+		: "r"(g1), "0"(o0)
+		: "cc");
+  __curbrk = (void *) o0;
+
+  if (__curbrk < addr)
+    {
+      __set_errno (ENOMEM);
+      return -1;
+    }
+
+  return 0;
+}
+weak_alias (__brk, brk)