компилировать стандартные программы на C (compile standard C programs)
Стандартный вывод сообщений (Stderr)
The standard error shall be used only for diagnostic messages.
If more than one pathname operand ending in .c (or possibly other
unspecified suffixes) is given, for each such file:
"%s:\n", <pathname>
may be written to allow identification of the diagnostic and
warning messages with the appropriate input file. These messages,
if written, shall precede the processing of each input file; they
shall not be written to the standard error if they are written to
the standard output, as described in the STDOUT section.
This utility may produce warning messages about certain
conditions that do not warrant returning an error (non-zero) exit
value.
