# Write a message to stderr.

message = strip( function( fmt; a2; a3; a4; a5; a6; a7; a8; a9; a10 )
{
    fprintf( "/dev/stderr"; "%s: %s: line %d: "; $program; file(); line() );
    fprintf( "/dev/stderr"; fmt; a2; a3; a4; a5; a6; a7; a8; a9; a10 );
    fprintf( "/dev/stderr"; "\n" );
} );