signal: Cope with C handler functions.
signal: Cope with C handler functions.

Fix a bug in setting symbolic (SIG_IGN/DFL) handlers.

Make setting handler to nil indistinguishable from setting to SIG_DFL.

zevv/luaposix,luaposix/luaposix,rrthomas/luaposix,ardje/luaposix,snegovick/luaposix,snegovick/luaposix,rrthomas/luaposix,jimmyharris/luaposix,zevv/luaposix,ardje/luaposix,jimmyharris/luaposix