--- a/libgo/runtime/go-signal.c	Thu Jun 11 23:10:03 2026
+++ b/libgo/runtime/go-signal.c	Thu Jun 25 13:58:01 2026
@@ -16,6 +16,27 @@
   #define SA_RESTART 0
 #endif
 
+#if defined(__i386__) && !defined(__amd64) && defined(__sun__) && defined(__svr4__) && !defined(REG_EAX)
+#define REG_EAX EAX
+#define REG_EBX EBX
+#define REG_ECX ECX
+#define REG_EDX EDX
+#define REG_EDI EDI
+#define REG_ESI ESI
+#define REG_EBP EBP
+#define REG_ESP ESP
+#define REG_EIP EIP
+#define REG_EFL EFL
+
+#undef REG_CS
+#define REG_CS CS
+#undef REG_FS
+#define REG_FS FS
+#undef REG_GS
+#define REG_GS GS
+
+#endif
+
 #ifdef USING_SPLIT_STACK
 
 extern void __splitstack_getcontext(void *context[10]);