stress-crypt: fix FreeBSD build issues

FreeBSD has crypt() and associated crypt structs declared in <unistd.h>
so fix libcrypt detection and builds for FreeBSD to not use <crypt.h>

Signed-off-by: Colin Ian King <colin.i.king@gmail.com>

stress-crypt.c

@@ -31,7 +31,8 @@ static const stress_help_t help[] = {
 };
 
 #if defined(HAVE_LIB_CRYPT) &&	\
-    defined(HAVE_CRYPT_H)
+    (defined(HAVE_CRYPT_H) || 	\
+     defined(__FreeBSD__))
 
 typedef struct {
 	const char *prefix;

test/test-libcrypt.c

@@ -21,7 +21,11 @@
 #define _XOPEN_SOURCE	600
 
 #include <string.h>
+#if defined(__FreeBSD__)
+#include <unistd.h>
+#else
 #include <crypt.h>
+#endif
 
 int main(void)
 {