Fix installation procedure: Now that os-inline.c is actually used (a recently

fixed bug prevented this) we need to also install os-include.c in addition to
os.h into the PREFIX/include/ location or building of module DSOs with APXS
fails.


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/1.3.x@82567 13f79535-47bb-0310-9956-ffa450edef68