package/gdb: fix musl build on riscv

Fix the following build failure raised since gdb 10.1 and
https://github.com/bminor/binutils-gdb/commit/bf84f7066626c78884436e1c39fb60f04c665f21:

../../gdbserver/linux-riscv-low.cc: In function 'void riscv_fill_fpregset(regcache*, void*)':
../../gdbserver/linux-riscv-low.cc:140:19: error: 'ELF_NFPREG' was not declared in this scope; did you mean 'ELF_NGREG'?
  140 |   for (i = 0; i < ELF_NFPREG - 1; i++, regbuf += flen)
      |                   ^~~~~~~~~~
      |                   ELF_NGREG

musl fixed the issue with
https://github.com/ifduyue/musl/commit/e5d2823631bbfebacf48e1a34ed28f28d7cb2570

Fixes:
 - http://autobuild.buildroot.org/results/16b19198980ce9c81a618b3f6e8dc9fe28247a28

Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
[yann.morin.1998@free.fr: use upstream repository for commit references]
Signed-off-by: Yann E. MORIN <yann.morin.1998@free.fr>
(cherry picked from commit 9d77dae55778eef05a90718f49914cf6eb3d6fc6)
[Peter: drop 11.1 patch]
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

package/gdb/10.2/0007-fix-musl-build-on-riscv.patch

@@ -0,0 +1,60 @@
+From c3fdbc0a24c83246f951ba79c7167547da979ae5 Mon Sep 17 00:00:00 2001
+From: Fabrice Fontaine <fontaine.fabrice@gmail.com>
+Date: Wed, 10 Nov 2021 23:14:54 +0100
+Subject: [PATCH] fix musl build on riscv
+
+Fix the following build failure raised with musl:
+
+../../gdbserver/linux-riscv-low.cc: In function 'void riscv_fill_fpregset(regcache*, void*)':
+../../gdbserver/linux-riscv-low.cc:140:19: error: 'ELF_NFPREG' was not declared in this scope; did you mean 'ELF_NGREG'?
+  140 |   for (i = 0; i < ELF_NFPREG - 1; i++, regbuf += flen)
+      |                   ^~~~~~~~~~
+      |                   ELF_NGREG
+
+musl fixed the issue with
+https://git.musl-libc.org/cgit/musl/commit/?id=e5d2823631bbfebacf48e1a34ed28f28d7cb2570
+
+Fixes:
+ - http://autobuild.buildroot.org/results/16b19198980ce9c81a618b3f6e8dc9fe28247a28
+
+Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
+---
+ gdb/nat/riscv-linux-tdesc.c  | 5 +++++
+ gdbserver/linux-riscv-low.cc | 5 +++++
+ 2 files changed, 10 insertions(+)
+
+diff --git a/gdb/nat/riscv-linux-tdesc.c b/gdb/nat/riscv-linux-tdesc.c
+index 837b1707e0f..667c013006a 100644
+--- a/gdb/nat/riscv-linux-tdesc.c
++++ b/gdb/nat/riscv-linux-tdesc.c
+@@ -31,6 +31,11 @@
+ # define NFPREG 33
+ #endif
+ 
++/* Work around musl breakage since version 1.1.24.  */
++#ifndef ELF_NFPREG
++# define ELF_NFPREG 33
++#endif
++
+ /* See nat/riscv-linux-tdesc.h.  */
+ 
+ struct riscv_gdbarch_features
+diff --git a/gdbserver/linux-riscv-low.cc b/gdbserver/linux-riscv-low.cc
+index 8bf97ea4aa3..1142dbc7b16 100644
+--- a/gdbserver/linux-riscv-low.cc
++++ b/gdbserver/linux-riscv-low.cc
+@@ -30,6 +30,11 @@
+ # define NFPREG 33
+ #endif
+ 
++/* Work around musl breakage since version 1.1.24.  */
++#ifndef ELF_NFPREG
++# define ELF_NFPREG 33
++#endif
++
+ /* Linux target op definitions for the RISC-V architecture.  */
+ 
+ class riscv_target : public linux_process_target
+-- 
+2.33.0
+