bash-mirror

Bash-5.3 patch 15: fix read builtin to avoid cases where -1 is used as an index into the input buffer

Bash-5.3 patch 14: update mapfile patch 11, removing stray line and improving the efficiency of the original fix

Bash-5.3 patch 13: fix technically undefined behavior when comparing return value from realloc to the original pointer

Bash-5.3 patch 12: fix subshells inappropriately running the EXIT trap if they receive a fatal signal before resetting traps

Bash-5.3 patch 11: fix mapfile problem when callback unsets the variable it is modifying