HTTP: include SSI header only where it's needed.

Previously, ngx_http_ssi_filter_module.h (optional HTTP module)
was pulled in by ngx_http.h (part of HTTP core).

Change-Id: Ie6fcc40037866b7ceb9755e0260b344d410b9235
Signed-off-by: Piotr Sikora <piotrsikora@google.com>
Reviewed-on: https://nginx-review.googlesource.com/1007
Reviewed-by: Martin Maly <mmaly@google.com>
diff --git a/src/http/modules/ngx_http_ssi_filter_module.c b/src/http/modules/ngx_http_ssi_filter_module.c
index 8236320..9f22184 100644
--- a/src/http/modules/ngx_http_ssi_filter_module.c
+++ b/src/http/modules/ngx_http_ssi_filter_module.c
@@ -8,6 +8,7 @@
 #include <ngx_config.h>
 #include <ngx_core.h>
 #include <ngx_http.h>
+#include <ngx_http_ssi_filter_module.h>
 
 #define NGX_HTTP_SSI_ERROR          1
 
diff --git a/src/http/modules/perl/ngx_http_perl_module.h b/src/http/modules/perl/ngx_http_perl_module.h
index 5e60b03..d15f546 100644
--- a/src/http/modules/perl/ngx_http_perl_module.h
+++ b/src/http/modules/perl/ngx_http_perl_module.h
@@ -14,6 +14,10 @@
 #include <ngx_http.h>
 #include <nginx.h>
 
+#if (NGX_HTTP_SSI)
+#include <ngx_http_ssi_filter_module.h>
+#endif
+
 #include <EXTERN.h>
 #include <perl.h>
 
diff --git a/src/http/ngx_http.h b/src/http/ngx_http.h
index 19cb680..13c3fee 100644
--- a/src/http/ngx_http.h
+++ b/src/http/ngx_http.h
@@ -44,9 +44,6 @@
 #if (NGX_HTTP_CACHE)
 #include <ngx_http_cache.h>
 #endif
-#if (NGX_HTTP_SSI)
-#include <ngx_http_ssi_filter_module.h>
-#endif
 #if (NGX_HTTP_SSL)
 #include <ngx_http_ssl_module.h>
 #endif