[libsoup] append_form_encoded: sync urlencode with php RFC1738 implementation.

[Dan Winship <danw src gnome org>]

commit 3acda7636ad2e116397aab913f6d8bb8f609715a
Author: Alban Browaeys <prahal yahoo com>
Date:   Mon Sep 23 15:12:25 2013 +0200

    append_form_encoded: sync urlencode with php RFC1738 implementation.
    
    From php_url_encode:
    /* Allow only alphanumeric chars and '_', '-', '.'; escape the rest */
    
    https://bugzilla.gnome.org/show_bug.cgi?id=708621

 libsoup/soup-form.c |    3 ++-
 1 files changed, 2 insertions(+), 1 deletions(-)
---
diff --git a/libsoup/soup-form.c b/libsoup/soup-form.c
index 5946dae..4dee564 100644
--- a/libsoup/soup-form.c
+++ b/libsoup/soup-form.c
@@ -218,7 +218,8 @@ append_form_encoded (GString *str, const char *in)
                if (*s == ' ') {
                        g_string_append_c (str, '+');
                        s++;
-               } else if (!g_ascii_isalnum (*s))
+               } else if (!g_ascii_isalnum (*s) && (*s != '-') && (*s != '_')
+                          && (*s != '.'))
                        g_string_append_printf (str, "%%%02X", (int)*s++);
                else
                        g_string_append_c (str, *s++);