xstr(1): various cleanup

[eadler]

Summary

• use char where possible
• avoid comma operator
• remove 'lint' support
• add attribute noreturn

[eadler]

use __dead2 instead of naked attribute

[des]

usr.bin/xstr/xstr.c

139–140

Pull up the else, or just remove it entirely as the result is the same either way (readstd ends up equal to zero).

235

This is unnecessary and forces the compiler to ensure that all arithemetic is done modulo 256, which may increase the code size.

276–277

This can also be written more legibly as

c = c << 3 + *cp++ - '0';

319

c must be an int for EOF detection to work reliably.

[eadler]

usr.bin/xstr/xstr.c

319

you're right. I forgot about this :\

[eadler]

per @des

[des]

I'm sorry for the lack of response, I thought this had landed already.

Upon closer inspection, I think I was mistaken about readstd, and the assignment to 0 is necessary. Have you tested all three possible cases (dash only, filenames only, both dash and filenames)?