[core] define __EXTENSIONS__ on Illumos

(thx devnexen)

src/first.h

@@ -19,6 +19,10 @@
 #endif
 #endif
 
+#if defined(__sun)
+#define __EXTENSIONS__
+#endif
+
 #ifndef __STDC_WANT_LIB_EXT1__
 #define __STDC_WANT_LIB_EXT1__ 1
 #endif

tests/fcgi-responder.c

@@ -11,6 +11,9 @@
  * Copyright(c) 2020 Glenn Strauss gstrauss()gluelogic.com  All rights reserved
  * License: BSD 3-clause (same as lighttpd)
  */
+#if defined(__sun)
+#define __EXTENSIONS__
+#endif
 
 #include <sys/types.h>
 #include <sys/socket.h>