MFC r294507,r294567,r299466:

MFC r294507,r294567,r299466:

r294507 (by harti):

Fill the ifAlias leaf of the ifXTable with the interface description
if there is one available and it fits into the maximum size (64 characters).

r294567 (by bz):

Change the variable to a #define in order to make gcc happy which
otherwise will complain about "variably modified 'alias' at file scope".
Unbreaks the build on gcc platforms.

r299466 (by cem):

bsnmpd: Fix size of trapsink::comm to match other community arrays

This fixes a number of possible strcpy() buffer overruns between the various
community strings in trap.c.

CIDs:		1006820, 1006821, 1006822

git-svn-id: svn://svn.freebsd.org/base/stable/10@301663 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f