Potentially underflow due to mal-aligned binary

[strazzere]

Found via fuzzing;

https://github.com/elfmaster/libelfmaster/blob/85e949c51b219594c0b3f4014cb09037f1442996/src/inte
rnal.c#L1329

This check will cause a malformed object to perform a (0 - 0) - 6 which will cause a very large number to be compared against i. Resulting in crashes often when ins[i] is used by the memcmp -- there needs to be a check to prevent this, likely returning 0.

Unsure if this needs to throw / catch extra issues downstream?