K 10
svn:author
V 6
kevans
K 8
svn:date
V 27
2020-04-06T23:16:05.137064Z
K 7
svn:log
V 469
yp*: fix -fno-common build

This is mostly two problems spread out far and wide:
- ypldap_process should be declared properly
- debug is defined differently in many programs

For the latter, just extern it and define it everywhere that actually needs
it. This mostly works out nicely for ^/libexec/ypxfr, which can remove the
assignment at the beginning of main in favor of defining it properly.

-fno-common will become the default in GCC10/LLVM11.

MFC after:	3 days

END