HTTP: avoid define-dependent fields in ngx_http_request_t.

Having those breaks binary compatibility between core HTTP modules
and optional HTTP modules that have either of those values defined.

Note that core defines (NGX_PCRE, NGX_STAT_STUB, NGX_HTTP_CACHE,
NGX_HTTP_GZIP, NGX_HTTP_SSL and NGX_HTTP_V2) are left untouched.

Change-Id: Ifceccfa0353c89f0de4d05ab9dab76e2e0ae2579
Signed-off-by: Piotr Sikora <piotrsikora@google.com>
Reviewed-on: https://nginx-review.googlesource.com/1008
Reviewed-by: Martin Maly <mmaly@google.com>

src/http/ngx_http_request.c

diff --git a/src/http/ngx_http_request.c b/src/http/ngx_http_request.c
index ab7c15f..394694a 100644
--- a/src/http/ngx_http_request.c
+++ b/src/http/ngx_http_request.c
@@ -149,19 +149,19 @@
     { ngx_string("Keep-Alive"), offsetof(ngx_http_headers_in_t, keep_alive),
                  ngx_http_process_header_line },
 
-#if (NGX_HTTP_X_FORWARDED_FOR)
+#if 1
     { ngx_string("X-Forwarded-For"),
                  offsetof(ngx_http_headers_in_t, x_forwarded_for),
                  ngx_http_process_multi_header_lines },
 #endif
 
-#if (NGX_HTTP_REALIP)
+#if 1
     { ngx_string("X-Real-IP"),
                  offsetof(ngx_http_headers_in_t, x_real_ip),
                  ngx_http_process_header_line },
 #endif
 
-#if (NGX_HTTP_HEADERS)
+#if 1
     { ngx_string("Accept"), offsetof(ngx_http_headers_in_t, accept),
                  ngx_http_process_header_line },
 
@@ -170,7 +170,7 @@
                  ngx_http_process_header_line },
 #endif
 
-#if (NGX_HTTP_DAV)
+#if 1
     { ngx_string("Depth"), offsetof(ngx_http_headers_in_t, depth),
                  ngx_http_process_header_line },
 

src/http/ngx_http_request.h

diff --git a/src/http/ngx_http_request.h b/src/http/ngx_http_request.h
index 967032a..8ecadd8 100644
--- a/src/http/ngx_http_request.h
+++ b/src/http/ngx_http_request.h
@@ -200,20 +200,20 @@
 
     ngx_table_elt_t                  *keep_alive;
 
-#if (NGX_HTTP_X_FORWARDED_FOR)
+#if 1
     ngx_array_t                       x_forwarded_for;
 #endif
 
-#if (NGX_HTTP_REALIP)
+#if 1
     ngx_table_elt_t                  *x_real_ip;
 #endif
 
-#if (NGX_HTTP_HEADERS)
+#if 1
     ngx_table_elt_t                  *accept;
     ngx_table_elt_t                  *accept_language;
 #endif
 
-#if (NGX_HTTP_DAV)
+#if 1
     ngx_table_elt_t                  *depth;
     ngx_table_elt_t                  *destination;
     ngx_table_elt_t                  *overwrite;