макропроцессор (macro processor)
Параметры (Options)
The m4 utility shall conform to the Base Definitions volume of
POSIX.1‐2017, Section 12.2, Utility Syntax Guidelines, except
that the order of the -D and -U options shall be significant, and
options can be interspersed with operands.
The following options shall be supported:
-s Enable line synchronization output for the c99
preprocessor phase (that is, #line directives).
-D name[=val]
Define name to val or to null if =val is omitted.
-U name Undefine name.
