Changed gmid.service to not to fork the server and forced to run under
user "gmid". gmid now waits for the network stack beeing available
before starting. Also "gmid" is now the syslog id.
Error and warning messages are prefixed with "error: " and "warning: "
correspondingly to ease integration with automated tooling.
`yywarn' function added. Off-by-one line numbers in warnings are fixed.
Two error messages are reworded to avoid repeating like
"error: error in server directive" or "error: syntax error".