Win32-specific build files.

Until the cmake build schema is entirely mature, these files
are needed for command-line builds of the 2.4 tree, and are
expected to change very little until the EOL of 2.4 branch.
The actual .dsp files are entirely unusable for any shipping
version of MSVC/Visual Studio, while the .mak exports of these
projects are usable on any flavor of the MS build environment.

git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.4.x@1736270 13f79535-47bb-0310-9956-ffa450edef68