getdirs.awk: restore regexp to original

Change-Id: I7f9714e1b0e079299c87b036dea8e91ffc701342
Removing obsolete _MINIX define

Change-Id: Id33ac7e973d1c0e249b690fe44a597474fac6076
Removing obsolete _MINIX_SOURCE define

Change-Id: I924d5af294cd5daf17c73f71803f060cea3c3d8b
Removing obsolete _MINIX_COMPAT define

Change-Id: If1f5901a53bbc454c04ee33ebb469a58f0566df7
Removing obsolete _NBSD_LIBC define

Change-Id: Ia6ce84ccdf36cf6f64540b990baaa7d85c53533d
Compatibility check for autotools

This add an explicit test on the obsolete _MINIX define, unset it and
replace it with _NETBSD_SOURCE.

This should help compile a lot of packages relying on autotools in pkgsrc.

Change-Id: Ie7da4ed5172f1b9f1f89e7a5d788ec2aed4d2563