devel/libunwind: Unbreak build on 32-bit ARM.

PR:		276346
Reported by:	John F. Carr <jfc@mit.edu>

devel/libunwind/files/patch-src_arm_Gtrace.c

@@ -0,0 +1,13 @@
+--- src/arm/Gtrace.c.orig	2023-12-22 11:34:31 UTC
++++ src/arm/Gtrace.c
+@@ -514,7 +514,9 @@ tdep_trace (unw_cursor_t *cursor, void **buffer, int *
+       if (likely(ret >= 0))
+         ACCESS_MEM_FAST(ret, c->validate, d, cfa + LINUX_SC_LR_OFF, lr);
+ #elif defined(__FreeBSD__)
+-      #error implement UNW_ARM_FRAME_SIGRETURN on FreeBSD
++      Dprintf ("%s: implement me\n", __FUNCTION__);
++      ret = -UNW_ESTOPUNWIND;
++      break;
+ #endif
+
+       /* Resume stack at signal restoration point. The stack is not