* #include can be followed by a macro name or a macro call

* In preproc_include, use preproc_call_expression

* Macro definition can contain continuation line in the argument list

* Reset grammar since line continuations are handled globally

Preserve the test.

* Parse expressions in preprocessor #if statement

* Make preproc_expression look like a normal expression

* Hide the wrapper rules
* Alias the rulres to match their corresponding expression rule
* Handle line continuations as extra tokens

Co-Authored-By: Thomas Johansen <thomasjo@gmail.com>

Signed-off-by: Nathan Sobo <nathan@github.com>

Signed-off-by: Nathan Sobo <nathan@github.com>

Signed-off-by: Nathan Sobo <nathan@github.com>

Doing this required treating the newline that follows these conditions as significant
in order to avoid conflicts, but this caused problems for error recovery.

Now there is never a need to mark a repeat rule as optional