$NetBSD: patch-src_zm_signal_cpp,v 1.3 2022/09/27 01:20:39 gdt Exp $

Don't assume machine-dependent IP register details are available for any
platform except Linux.  Only Linux is sure to have this style of mcontext_t.

Resolves build on systems that have ucontext_t but an mcontext_t that
doesn't look like Linux.

--- src/zm_signal.cpp.orig	2019-02-23 04:38:47.000000000 +1300
+++ src/zm_signal.cpp	2022-01-18 00:42:50.000000000 +1300
@@ -66,13 +66,17 @@
 	    #ifdef __FreeBSD_kernel__
 		ip = (void *)(uc->uc_mcontext.mc_rip);
 	    #else
+		#if defined(__linux__)
 		ip = (void *)(uc->uc_mcontext.gregs[REG_RIP]);
+		#endif
 	    #endif
     #else
 	    #ifdef __FreeBSD_kernel__
 		ip = (void *)(uc->uc_mcontext.mc_eip);
 	    #else
+		#if defined(__linux__)
 		ip = (void *)(uc->uc_mcontext.gregs[REG_EIP]);
+		#endif
 	    #endif
     #endif				// defined(__x86_64__)