AT&T C compilers

[Guy Harris]

> The c compiler that came with the system VS Gnu-c
>% cc tmp.c
>"tmp.c", line 4: warning: old-fashioned assignment operator

You have an old C compiler.  Neither the System V version of PCC nor the one
shipped with SunOS 4.0 support old-fashioned assignment operators;
"x=-1" is interpreted by both as "assign -1 to x".

>Atleast UNIX could have implemented the ANSI Prototypes and gotten rid
>of this bug.

I don't know what "the ANSI Prototypes" means here, but if it means
"function prototypes" it wouldn't have made a bit of difference to the
interpretation of "x=-1".  If it were a full (p)ANS C compiler, it would
have interpreted "x=-1" properly, but just implementing prototypes does
not a full (p)ANS C compiler make.

There are several different UNIX C compilers, not least because there
are several different architectures that support UNIX.  Not all of them
have been "modernized" to the same degree.  The BSD compiler doesn't
seem to have been modernized in this regard.