sys/socket.h cannot compile without _NETBSD_SOURCE

[sgerraty]

I was recently trying to build latest bmake on minix 3.2.0 and found it necessary to add -D_NETBSD_SOURCE to CPPFLAGS else many headers did not work correctly.
In some headers I see #if defined(_NETBSD_SOURCE) || defined(__minix) but others like sys/socket.h only check for _NETBSD_SOURCE.

I also found it necessary to tweak the filtering of several unit-tests due to seemingly gratuitous differences in error messages like file name too long rather than File name too long and no such file or directory rather than. No such....

[petershh]

Hello,
Are these flags applied in Minix master?

Please note that porting NetBSD userland to Minix is work-in-progress, and things may work incorrectly.