fix compiler warning: external definition with no prior declaration

lib/parsedate.c

@@ -83,6 +83,7 @@
 #endif
 
 #include <curl/curl.h>
+#include "parsedate.h"
 
 const char * const Curl_wkday[] =
 {"Mon", "Tue", "Wed", "Thu", "Fri", "Sat", "Sun"};

tests/libtest/lib506.c

@@ -15,8 +15,8 @@
 
 #include <curl/mprintf.h>
 
-const char *HOSTHEADER = "Host: www.host.foo.com";
-const char *JAR = "log/jar506";
+static const char *HOSTHEADER = "Host: www.host.foo.com";
+static const char *JAR = "log/jar506";
 #define THREADS 2
 
 /* struct containing data of a thread */