wget: allow end-users to customize Content-Type for --post-data and --post-file

More explanation in this PR:
https://github.com/rmyorston/busybox-w32/pull/233

The real use-case:
wget https://api.github.com/markdown/raw --header "Content-Type: text/plain"

function                                             old     new   delta
wget_main                                           2560    2581     +21
wget_user_headers                                     62      76     +14
.rodata                                           104196  104197      +1
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 3/0 up/down: 36/0)               Total: 36 bytes

Signed-off-by: Ildar Shaimordanov <ildar.shaimordanov@gmail.com>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

1 files changed, 22 insertions, 13 deletions

diff --git a/networking/wget.c b/networking/wget.c
index 91ef99eab..9ec0e67b9 100644
--- a/networking/wget.c
+++ b/networking/wget.c
@@ -211,29 +211,33 @@ enum {
         HDR_HOST          = (1<<0),
         HDR_USER_AGENT    = (1<<1),
         HDR_RANGE         = (1<<2),
-        HDR_AUTH          = (1<<3) * ENABLE_FEATURE_WGET_AUTHENTICATION,
-        HDR_PROXY_AUTH    = (1<<4) * ENABLE_FEATURE_WGET_AUTHENTICATION,
+        HDR_CONTENT_TYPE  = (1<<3),
+        HDR_AUTH          = (1<<4) * ENABLE_FEATURE_WGET_AUTHENTICATION,
+        HDR_PROXY_AUTH    = (1<<5) * ENABLE_FEATURE_WGET_AUTHENTICATION,
 };
 static const char wget_user_headers[] ALIGN1 =
         "Host:\0"
         "User-Agent:\0"
         "Range:\0"
+        "Content-Type:\0"
 # if ENABLE_FEATURE_WGET_AUTHENTICATION
         "Authorization:\0"
         "Proxy-Authorization:\0"
 # endif
         ;
-# define USR_HEADER_HOST       (G.user_headers & HDR_HOST)
-# define USR_HEADER_USER_AGENT (G.user_headers & HDR_USER_AGENT)
-# define USR_HEADER_RANGE      (G.user_headers & HDR_RANGE)
-# define USR_HEADER_AUTH       (G.user_headers & HDR_AUTH)
-# define USR_HEADER_PROXY_AUTH (G.user_headers & HDR_PROXY_AUTH)
+# define USR_HEADER_HOST         (G.user_headers & HDR_HOST)
+# define USR_HEADER_USER_AGENT   (G.user_headers & HDR_USER_AGENT)
+# define USR_HEADER_RANGE        (G.user_headers & HDR_RANGE)
+# define USR_HEADER_CONTENT_TYPE (G.user_headers & HDR_CONTENT_TYPE)
+# define USR_HEADER_AUTH         (G.user_headers & HDR_AUTH)
+# define USR_HEADER_PROXY_AUTH   (G.user_headers & HDR_PROXY_AUTH)
 #else /* No long options, no user-headers :( */
-# define USR_HEADER_HOST       0
-# define USR_HEADER_USER_AGENT 0
-# define USR_HEADER_RANGE      0
-# define USR_HEADER_AUTH       0
-# define USR_HEADER_PROXY_AUTH 0
+# define USR_HEADER_HOST         0
+# define USR_HEADER_USER_AGENT   0
+# define USR_HEADER_RANGE        0
+# define USR_HEADER_CONTENT_TYPE 0
+# define USR_HEADER_AUTH         0
+# define USR_HEADER_PROXY_AUTH   0
 #endif
 
 /* Globals */
@@ -1261,8 +1265,13 @@ static void download_one_url(const char *url)
                 }
 
                 if (G.post_data) {
+                        /* If user did not override it... */
+                        if (!USR_HEADER_CONTENT_TYPE) {
+                                SENDFMT(sfp,
+                                        "Content-Type: application/x-www-form-urlencoded\r\n"
+                                );
+                        }
                         SENDFMT(sfp,
-                                "Content-Type: application/x-www-form-urlencoded\r\n"
                                 "Content-Length: %u\r\n"
                                 "\r\n"
                                 "%s",