Bristol Junction from Bristol Temple Meads is operated by South Western Railway, and there are scheduled coach links to most major UK cities. The M4 motorway connects the city on an east-west axis from London to West Wales, and the M5 is a north–south west axis from Birmingham to Exeter. The M49 motorway is a shortcut between the M5 in the south and the M4 Severn Crossing in the west, and the M32 is a spur from the M4 to the city centre. The Portway connects the M5 to the city centre, and was the most expensive road in Britain when
M4 (computer language) FreeBSD, NetBSD, and OpenBSD provide independent implementations of the m4 language. Furthermore, the Heirloom Project Development Tools includes a free version of the m4 language, derived from OpenSolaris. "GNU m4" is an implementation of m4 for the GNU Project. It is designed to avoid many kinds of arbitrary limits found in traditional m4 implementations, such as maximum line lengths, maximum size of a macro and number of macros. Removing such arbitrary limits is one of the stated goals of the GNU Project. The GNU Autoconf package makes extensive use of the features of GNU m4. GNU m4 is currently maintained