Preprocessor: Token pasting in function-like macro with no LHS causes crash

[ehaas]

#define bar(a) ## i

thread 14036537 panic: integer overflow
/Users/ehaas/source/arocc/src/Preprocessor.zig:1253:63: 0x1013ad8e6 in Preprocessor.defineFn (arocc)
                if (pp.token_buf.items[pp.token_buf.items.len - 1].id == .macro_param) {
                                                              ^
/Users/ehaas/source/arocc/src/Preprocessor.zig:1143:53: 0x10137d24b in Preprocessor.define (arocc)
        if (first.id == .l_paren) return pp.defineFn(tokenizer, macro_name, first);
                                                    ^
/Users/ehaas/source/arocc/src/Preprocessor.zig:264:53: 0x101371576 in Preprocessor.preprocess (arocc)
                    .keyword_define => try pp.define(&tokenizer),
                                                    ^
/Users/ehaas/source/arocc/src/main.zig:237:22: 0x1013557a8 in processSource (arocc)
    try pp.preprocess(source);
                     ^
/Users/ehaas/source/arocc/src/main.zig:223:22: 0x10134a161 in handleArgs (arocc)
        processSource(comp, source, builtin, user_macros) catch |e| switch (e) {
                     ^
/Users/ehaas/source/arocc/src/main.zig:41:15: 0x1013472ed in main (arocc)
    handleArgs(&comp, args) catch |err| switch (err) {
              ^
/Users/ehaas/source/zig/build/lib/zig/std/start.zig:524:29: 0x1013c4d7c in std.start.callMain (arocc)
            return root.main();
                            ^
/Users/ehaas/source/zig/build/lib/zig/std/start.zig:469:12: 0x10134b267 in std.start.callMainWithArgs (arocc)
    return @call(.{ .modifier = .always_inline }, callMain, .{});
           ^
/Users/ehaas/source/zig/build/lib/zig/std/start.zig:434:12: 0x10134b1a5 in std.start.main (arocc)
    return @call(.{ .modifier = .always_inline }, callMainWithArgs, .{ @intCast(usize, c_argc), c_argv, envp });
           ^
???:?:?: 0x7fff204ecf3c in ??? (???)
???:?:?: 0x1 in ??? (???)
[1]    19263 abort      ./zig-out/bin/arocc test/cases/tokenpaste.c

[doppioandante]

Should be easy to fix, let me try