Some packages in develop will not build because of underscores in PKG_NAME

[Hugh]

for opkg_utils/opkg-build, PKG_NAME must include only a-z, 0-9 or +- characters. some packages in the repo include underscores, and they subsequently will not pack into ipks

eg:
Package: atm-svc_recv
Package: atm-svc_send
Package: atm-ttcp_atm

[Hugh]

need to look at what the best solution to this is, replacing the underscores, modifying the opkg-build script (to allow _), etc

all seem to have drawbacks

[Hugh]

commit c6b65ad