bug#24451: grep -Tn misbehaves under Emacs shell

[Paul Eggert]

Tags: patch

While looking into something else I noticed that 'grep -T' does not work 
under an Emacs shell window. grep outputs tab-backspace-':'-C to align C 
to the next tab stop, but under Emacs the backspace undoes the tab and 
so the output is not aligned. Arguably this is a problem with Emacs, but 
even if Emacs were changed the grep approach is not portable: Vim 
displays "^H:" instead, for example, and this also breaks alignment. 
grep should use a tab character to go to the next tab stop; this is more 
reliable and is simpler.

While in the neighborhood I noticed that -Tn alignment does not work for 
files that are sufficiently large (10,000 lines, say). Plus, nowadays we 
can rely on PRIuMAX to simplify printf.

Proposed patches attached. Normally I'd just install this sort of thing, 
but since we have a release candidate out I thought I'd ask first.

0001-grep-simplify-by-using-PRIuMAX.patch
Description: Source code patch

0002-grep-T-no-longer-outputs-BS.patch
Description: Source code patch

0003-grep-T-now-adjusts-number-widths-for-worst-case.patch
Description: Source code patch