For autoconf-based builds, DEFAULT_REL_RUNTIMEDIR is defined by the layout machinery, which creates ap_config_layout.h.
For non-autoconf-based builds, there is no equivalent to ap_config_layout.h. Windows and NetWare MPMs define DEFAULT_REL_RUNTIMEDIR in mpm_layout.h, but that is local to the MPM. So no definition is visible to modules and other source files. As a work-around, several common source files have created their own defaults when DEFAULT_REL_RUNTIMEDIR is not defined. The attached patch creates a new os_layout.h for non-autoconf-based builds (just Windows and NetWare) which defines DEFAULT_REL_RUNTIMEDIR. The workarounds from the several common source files are removed. Third-party modules can also depend on DEFAULT_REL_RUNTIMEDIR again. Concerns (such as better name for the new file)? No, I didn't test it :) My Visual C++ Express setup for httpd is not workable at present. I will try to test the docgen stuff before I commit.
