The C compiler provided with Alpha OSF/1 V4.0 (a.k.a. Digital UNIX)
defaults to an extended K&R C mode, not ANSI C. You need to provide
the -std argument to the compiler (i.e., ./configure
CC='cc -std') to enable extended ANSI C mode. More recent versions
of the operating system, such as 5.0, seem to have C compilers which
default to -std.