Foreign declarations have been a bad idea. This became clear after
implementing indirect calls, because as a consequence you get 'used but
not declared' warnings for calls to foreign functions, too. I could
'fix' that with a bit of effort, but that would be misplaced. The C
compiler will warn about undeclared variables and functions anyway, so
why bother? If you really want to know, perhaps for debugging, use -W
option for extra warnings. If you do, you'll now get the more precise
waring 'treating undeclared object xxx as foreign'.

This simply replaces 'ident ( args )' with  'expr ( args )' in the
syntax. A few more changes in the code generator and we're done.

Members are no longer identified with variables in the syntax. Member
selection "operators" ('.' and '->') are no longer treated as binary
operators. Instead, member selection gets a new syntax node type E_SELECT,
and members (only allowed as rhs of a member selection) are not E_VAR, but
E_MEMBER. This all works because members are not first class in C, that is
"x.(name)" is a syntax error.

This is a simple solution for the recurring annoyance of snc issuing
"undefined variable" warnings.

Declaring members in a foreign declaration becomes obsolete.

This appeared when compiling deeply nested statements.
The solution is to use a dynamically growing stack.

As turned out, the 2.0.x branch supported this, so it is added
for compatibility.

Associating a queue with an event flag is unnecessary. An event
flag can be sync'ed with the variable or not; we can regard
the old form for the syncq clause as syntactic sugar for the new
form plus an additional sync clause.

These types are named like the standard C99 types, but are
implemented using epicsTypes.h since the C99 inttypes.h cannot
be assumed to be available on all platforms. We only add
integer types with sizes up to 32, since 64 bit types are not
supported by CA and epicsTypes defines them only if C99 is enabled.

Goes like "when (<cond>) {<actions>} exit and has same effect as
(and is implemented by) calling built-in pvExit.

This was broken by the addition of "assign x;" syntax.
E_INIT will be used for array initializers, too (thus the name).

Foreign declarations now use "foreign" instead of "declare".
Added keyword "connect" as a synonym for "assign".
Added non-terminals "variable" and "event_flag" to the grammar;
these are documentary aliases for terminal NAME.

Also added string typedef to generated code.

Instead added a special case to the expr function in parse.c

It is hopefully a bit clearer now what is allowed and what is not.
Unfortunately the semantics of sync and syncQ is still a mess.