bsd.endian.mk: Allow for the cross building case

[imp]

Summary

We need to include bsd.endian.mk from bsd.compiler.mk to enable
compressed symbols only on FreeBSD little endian targets.

However, since we include bsd.compiler.mk from Makefile.inc1 and from
the build tools makefiles, it has to work on Linux and osx. Make the
error condition only when we're building natively (so that we are
forced to add a new architecture to the list).

Otherwise, define bogus, poisoned values and leave TARGET_ENDIANNESS
undefined. Since we don't actually use TARGET_ENDIANNESS for anything in
the cross building phase, these values are a failsafe agianst their
use. The one place that detects endian is appropriately protected.

[jrtc27]

Won't referencing the variables always be an error if they're undefined, which simplifies things as you don't need to make sure nothing does .if endian == 1234 .else .endif or similar?

[emaste]

share/mk/bsd.endian.mk

18–29

maybe .elif to avoid a level of nesting?

19–29

these quotes are unnecessary (they're just emitted verbatim in the error output)

[imp]

In D33742#762970, @jrtc27 wrote:

Won't referencing the variables always be an error if they're undefined, which simplifies things as you don't need to make sure nothing does .if endian == 1234 .else .endif or similar?

${CAP_MKDB_ENDIAN} and ${LOCALDEV_ENDIAN} are expanded to nothing in that case, and the commands will work w/o the usual arg. Some of the makefiles include them for that
without checking TARGET_ENDIANNESS.

You are right about the target endianness being undefined. I'll leave the comment and the two failsafe values, but leave that undefined. I'll also modify the bsd.compiker.mk
change to just refer to the comment in bsd.endian.mk and leave the code as-is there. I'll drop the 'assert' patch from the series too.

[imp]

review comments

[imp]

updated commit message

[imp]

ubuntu and amd64 build, running make tinderbox now