bsd.progs.mk: Fix incremental META_MODE for prog sourcesHEADmain

This fixes recursed builds not having meta mode enabled for them which
disabled dependency and and command change tracking.  We only want common
objects marked .NOMETA when recursing, not non-common objects.  The
common code expects _PROGS_COMMON_SRCS does not contain the prog source
or else it will be marked .NOMETA.

Add comments explaining the intent and cases being covered.

Fixes:	4ea5e107b1 ("<bsd.progs.mk>: Allow using SRCS for common sources")
Differential Revision:	https://reviews.freebsd.org/D55711
Reviewed by:	vexeduxr, sjg

0 files changed, 0 insertions, 0 deletions