bug#63957: 29.0.91; c-ts-mode: incorrect fontification in alloc.c

[Eli Zaretskii]

> From: Yuan Fu <casouri@gmail.com>
> Date: Mon, 12 Jun 2023 02:16:51 -0700
> Cc: Theodor Thornhill <theo@thornhill.no>,
>  63957@debbugs.gnu.org
> 
> If we add preproc directives:
> 
> struct A
> {
> #if A
>   int a;
> #else  
>   int b;
> }
> #endif
> 
> Now the parser will parse the "struct A {“ individually; parse “int a;” 
> individually; and parse “int b; }” individually.
> 
> So in general, if a preproc directives butchers some construct, the first 
> part is usually fine (eg, the “struct A {“ part), but the rest often have 
> problems. Like a dangling “else if {}” in if-else-if, or a dangling “xxx }” 
> in a function definition, or maybe a “default: xxx }” in a switch-case.

Thanks.