build: Allow for custom server config directory
Most X servers, even those which do not have specific configuration files, can use the directory specified by SERVER_MISC_CONFIG_PATH when they have the XCSECURITY extension enabled, because this is also where the "protocol.txt" file is searched for at runtime.
Unfortunately, the SERVER_MISC_CONFIG_PATH is set from serverconfigdir
which is hardcoded in the build system to "prefix/
libdir/xorg", and
all X server builds share the same path.
That makes it harder for having different X servers such as Xwayland to install in the same path without sharing the same server configuration path (and hence the same "protocol.txt" file).
Allow for the customization of server configuration path from the build options so that different X servers can use completely different and independent paths.
Signed-off-by: Olivier Fourdan ofourdan@redhat.com