Make sgen compile on OpenBSD, by adding the missing stuff

configure.in

@@ -2129,7 +2129,7 @@ case "$host" in
 		  haiku*)
 			LIBC=libroot.so
 			;;
-		  linux*|darwin*)
+		  linux*|darwin*|openbsd*)
 			sgen_supported=true
 		        ;;
 		esac
@@ -2140,7 +2140,7 @@ case "$host" in
 		JIT_SUPPORTED=yes
 		jit_wanted=true
 		case $host_os in
-		  linux*|darwin*)
+		  linux*|darwin*|openbsd*)
 			sgen_supported=true
 			;;
 		esac

mono/metadata/sgen-gc.c

@@ -4565,11 +4565,12 @@ suspend_handler (int sig, siginfo_t *siginfo, void *context)
 	int old_errno = errno;
 	gpointer regs [ARCH_NUM_REGS];
 	gpointer stack_start;
+	ucontext_t *ctx = (ucontext_t*)context;
 
 	id = pthread_self ();
 	info = mono_sgen_thread_info_lookup (id);
 	info->stopped_domain = mono_domain_get ();
-	info->stopped_ip = (gpointer) ARCH_SIGCTX_IP (context);
+	info->stopped_ip = (gpointer) ARCH_SIGCTX_IP (ctx);
 	stop_count = global_stop_count;
 	/* duplicate signal */
 	if (0 && info->stop_count == stop_count) {
@@ -4580,13 +4581,13 @@ suspend_handler (int sig, siginfo_t *siginfo, void *context)
 	/* update the remset info in the thread data structure */
 	info->remset = remembered_set;
 #endif
-	stack_start = (char*) ARCH_SIGCTX_SP (context) - REDZONE_SIZE;
+	stack_start = (char*) ARCH_SIGCTX_SP (ctx) - REDZONE_SIZE;
 	/* If stack_start is not within the limits, then don't set it
 	   in info and we will be restarted. */
 	if (stack_start >= info->stack_start_limit && info->stack_start <= info->stack_end) {
 		info->stack_start = stack_start;
 
-		ARCH_COPY_SIGCTX_REGS (regs, context);
+		ARCH_COPY_SIGCTX_REGS (regs, ctx);
 		info->stopped_regs = regs;
 	} else {
 		g_assert (!info->stack_start);
@@ -4594,7 +4595,7 @@ suspend_handler (int sig, siginfo_t *siginfo, void *context)
 
 	/* Notify the JIT */
 	if (gc_callbacks.thread_suspend_func)
-		gc_callbacks.thread_suspend_func (info->runtime_data, context);
+		gc_callbacks.thread_suspend_func (info->runtime_data, ctx);
 
 	DEBUG (4, fprintf (gc_debug_file, "Posting suspend_ack_semaphore for suspend from %p %p\n", info, (gpointer)ARCH_GET_THREAD ()));
 	/* notify the waiting thread */

mono/metadata/sgen-gc.h

@@ -178,7 +178,7 @@ struct _GCMemSection {
 
 typedef struct _SgenPinnedChunk SgenPinnedChunk;
 
-#ifdef __APPLE__
+#if defined(__APPLE__) || defined(__OpenBSD__)
 const static int suspend_signal_num = SIGXFSZ;
 #else
 const static int suspend_signal_num = SIGPWR;

mono/utils/mono-sigcontext.h

@@ -112,6 +112,10 @@
 	#define UCONTEXT_REG_RSI(ctx) ((ctx)->sc_rsi)
 	#define UCONTEXT_REG_RDI(ctx) ((ctx)->sc_rdi)
 	#define UCONTEXT_REG_RIP(ctx) ((ctx)->sc_rip)
+	#define UCONTEXT_REG_R8(ctx) ((ctx)->sc_r8)
+	#define UCONTEXT_REG_R9(ctx) ((ctx)->sc_r9)
+	#define UCONTEXT_REG_R10(ctx) ((ctx)->sc_r10)
+	#define UCONTEXT_REG_R11(ctx) ((ctx)->sc_r11)
 	#define UCONTEXT_REG_R12(ctx) ((ctx)->sc_r12)
 	#define UCONTEXT_REG_R13(ctx) ((ctx)->sc_r13)
 	#define UCONTEXT_REG_R14(ctx) ((ctx)->sc_r14)