Configure server address via commandline flag.

extension/liba3web.go

@@ -18,9 +18,10 @@ import "C"
 import (
 	"fmt"
 	"log"
+	"net/http"
+	"os"
 	"strings"
 	"unsafe"
-	"net/http"
 )
 
 var cb C.callbackProc
@@ -45,6 +46,17 @@ func RVExtensionVersion(output *C.char, outputsize C.size_t) {
 	defer C.free(unsafe.Pointer(version))
 	var size = C.min(C.strlen(version)+1, outputsize-1)
 	C.strncpy(output, version, size)
+
+	args := os.Args[1:]
+	for _, arg := range args {
+		if strings.Index(arg, "-a3webserver") == 0 {
+			s := strings.Split(arg, "=")
+			if len(s) == 2 {
+				serverURL = s[1]
+				break
+			}
+		}
+	}
 }
 
 // RVExtensionArgs STRING callExtension ARRAY