meson: fix FreeBSD -Wl,--version-script detection
Bump required meson version
`has_link_argument` and `has_multi_link_arguments` require meson >= 0.46
Support clang linker using -exported_symbols_list
Detection for `-exported_symbol` doesn't work,
and it doesn't accept wildcards anyway.
Use `-exported_symbols_list`, which works and is documented.
meson: group add_project_arguments calls
Implemented ulimit builtin
Abort when unspecified commands are attempted
Adding getopt implementation
It's pretty simple but I think it covers all of items described in the
Very basic umask implementation
Doesn't yet support the -S flag, or symbolic modes, but does allow for
getting and setting the umask.
Add meson option for readline
Move frontend_* -> frontend/*
Drop minimum meson version to 0.37.1
The minimum required meson version is 0.43.0, but no features are
actually being used that are incompatible with 0.37.1 (the latest
version shipped by Debian).
Add support for IO redirections in builtins
Add frontend_ prefix to frontend files
Do not use shm_open for command substitution
Use pipes instead. This has the drawback of blocking the shell while reading.
Rename source builtin to dot
For consistency with POSIX
shell: make AST const, fix memory leaks