Adds support to libmemcached into the build system

Libmemcached will be further used to handle centralized collections.

ext/Makefile.am

@@ -3,6 +3,7 @@ EXT_CFLAGS = -I../apache2 \
     @APR_CFLAGS@ \
     @APU_CFLAGS@ \
     @APXS_CFLAGS@ \
+    @LIBMEMCACHED_CFLAGS@ \
     @LIBXML2_CFLAGS@ \
     @LUA_CFLAGS@ \
     @SSDEEP_CFLAGS@
@@ -12,6 +13,7 @@ EXT_CPPFLAGS = @APR_CPPFLAGS@ \
     
 EXT_LIBADD = @APR_LDADD@ \
     @APU_LDADD@ \
+    @LIBMEMCACHED_LDADD@ \
     @LIBXML2_LDADD@ \
     @LUA_LDADD@
 
@@ -19,6 +21,7 @@ EXT_LDFLAGS = -no-undefined -module -avoid-version \
     @APR_LDFLAGS@ \
     @APU_LDFLAGS@ \
     @APXS_LDFLAGS@ \
+    @LIBMEMCACHED_LDFLAGS@ \
     @LIBXML2_LDFLAGS@ \
     @LUA_LDFLAGS@ \
     @SSDEEP_LDFLAGS@