Solaris <string.h> does not declare 'strdup' if _XOPEN_SOURCE is

defined.

(Preprocessor symbols such as _POSIX_C_SOURCE or _XOPEN_SOURCE are
supposed to disable anything not allowed by the respective
specification; I'm not sure why 'strdup' would be considered
an outlaw though.)

crypto/engine/enginetest.c

@@ -63,7 +63,7 @@
 # define _XOPEN_SOURCE_EXTENDED
 #endif
 #ifdef OPENSSL_SYS_UNIX
-# define _XOPEN_SOURCE
+/* # define _XOPEN_SOURCE */
 # define _XOPEN_SOURCE_EXTENDED	/* For Linux and probably anything GNU */
 #endif
 #include <stdio.h>