Expose more headers with NGX_HTTP_HEADERS.

src/http/ngx_http_request.c

diff --git a/src/http/ngx_http_request.c b/src/http/ngx_http_request.c
index a2663f0..89cfe77 100644
--- a/src/http/ngx_http_request.c
+++ b/src/http/ngx_http_request.c
@@ -140,7 +140,7 @@
                  offsetof(ngx_http_headers_in_t, upgrade),
                  ngx_http_process_header_line },
 
-#if (NGX_HTTP_GZIP)
+#if (NGX_HTTP_GZIP || NGX_HTTP_HEADERS)
     { ngx_string("Accept-Encoding"),
                  offsetof(ngx_http_headers_in_t, accept_encoding),
                  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 ead3238..5d44c06 100644
--- a/src/http/ngx_http_request.h
+++ b/src/http/ngx_http_request.h
@@ -200,7 +200,7 @@
     ngx_table_elt_t                  *expect;
     ngx_table_elt_t                  *upgrade;
 
-#if (NGX_HTTP_GZIP)
+#if (NGX_HTTP_GZIP || NGX_HTTP_HEADERS)
     ngx_table_elt_t                  *accept_encoding;
     ngx_table_elt_t                  *via;
 #endif