fix: Typo in a preprocessor directive

This is a regression of commit 2519a03418af2108d3bd8c269ba01ab72ae240ef
"refactor: Clean up the checking of chunk lengths and allocation limits"

Compilation would break under the "right" non-default configuration.
(Oopsie!)

Also clean up comments in the surrounding code.

Reported-by: chris0e3 <chris0e3@gmail.com>
Signed-off-by: Cosmin Truta <ctruta@gmail.com>
1 file changed