Hi, When trying to build the modular X server, the build died in configure with this message: checking for LIBDRM... configure: error: Package requirements (libdrm) were not met. Consider adjusting the PKG_CONFIG_PATH environment variable if you installed software in a non-standard prefix. Alternatively you may set the LIBDRM_CFLAGS and LIBDRM_LIBS environment variable s to avoid the need to call pkg-config. See the pkg-config man page for more details. After installing libdrm-devel the problem went away. I think you probably have a missing BuildRequires for libdrm-devel in the xorg-x11-server spec file.
Fixed in xorg-x11-server-0.99.3-6