diff --git a/lib/zig.h b/lib/zig.h
index f2faed0b376201db96a464f6c1394f2fc26f8aa8..ad9b51e96be8b0be39891e5fd16bd837449a0324 100644
--- a/lib/zig.h
+++ b/lib/zig.h
@@ -124,8 +124,8 @@
 #elif defined(__OpenBSD__)
 #define zig_openbsd
 #define zig_bsd
-#elif defined(__SVR4)
-#define zig_solaris
+#elif defined(__illumos__)
+#define zig_illumos
 #elif defined(__wasi__)
 #define zig_wasi
 #elif defined(_WIN32)