libwmf: depends on jpeg

Closes #28584.
par2: fix assert failure

Closes #28795.
Closes #28796.

Signed-off-by: Jack Nagel <jacknagel@gmail.com>
Modify the brew script to use the builtin cd, pwd, unset, and exec commands

The allows brew to continue working in cases where the user has defined
a funtion named cd, pwd, or etc.