Not very useful currently, but let's add non-destructive patterns later.

Seriously, all the string handling needs to be rewritten...

Same as #strlen except for ignoring color codes.

Needs cmake to be configured with -coverage for CFLAGS.

The behaviour did differ based on contents of unrelated memory...

The variable being named "flag" didn't improve readability any, either.

Seems woefully buggy, but fixing that is for later.

The former is a complex function, despite no single-byte values above 127
being alphanumeric -- glibc still lives in pre-Unicode days.

Stepping through the former is a hell.

The fallback logic in the kernel works well, only concern are old kernels,
old headers, non-Linux kernels (until the latter grow support).