Compilation error after redesign of the archive modules

Hi,
With the redesign of the archive modules:
35739b87dcfef9fc0186aca659f262746fecd778 - Redesign archive modules
if we were to compile basic_archive module with USE_PGXS=1, we get
compilation error:

[]$ make USE_PGXS=1
gcc -std=gnu99 -Wall -Wmissing-prototypes -Wpointer-arith
-Wdeclaration-after-statement -Werror=vla -Wendif-labels
-Wmissing-format-attribute -Wformat-security -fno-strict-aliasing
-fwrapv -fexcess-precision=standard -g -g -O0 -fPIC
-fvisibility=hidden -I. -I./
-I/home/sravanv/work/workspaces/PGdevel_test/include/postgresql/server
-I/home/sravanv/work/workspaces/PGdevel_test/include/postgresql/internal
-D_GNU_SOURCE -I/usr/include/libxml2 -c -o basic_archive.o
basic_archive.c -MMD -MP -MF .deps/basic_archive.Po
basic_archive.c:33:36: fatal error: archive/archive_module.h: No such
file or directory
#include "archive/archive_module.h"
^
compilation terminated.
make: *** [basic_archive.o] Error 1

I have attached a patch that fixes the problem. Can you please review
if it makes sense to push this patch?

--
Thanks & Regards,
Sravan Velagandula
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company