Makefile.inc1: Set LC_COLLATE in distributeworld for glibc compatibility

distributeworld relies on "foo" sorting directly before "foo type=...",
but with glibc both en_US and en_GB have "fooa" sort between "foo" and
"foo z", resulting in some files (in particular, id due to "ident"
sorting before "id type=" but after "id") not being included in the meta
files and thus not included in the dist tarballs. Forcing use of the C
locale ensures this does not occur.

Reviewed by: brooks
Obtained from: CheriBSD
Differential Revision: https://reviews.freebsd.org/D35812