When building xserver with slibtool (https://dev.midipix.org/cross/slibtool) the build will fail.
/usr/bin/ld: cannot find -ldmxconfig
This is because xserver creates libdmxconfig.a internally and then links with the linker flag -ldmxconfig. However according to automake documentation the -lfoo linker flags should only be used for external dependencies and all internal libraries should be linked with the libtool archive file (.la) or the static archive (.a) when the former is not available.
GNU libtool is far more permissive and happens to silently obscure this issue while slibtool fails because it instead sees '-L./.libs -ldmxconfig'.