Allow the nodemap to contain multiple nodes for mibs like IF-MIB

In the IF-MIB, "interfaces" and "ifMIBObjects" both contain
significant subtrees.  Allow nodemap to contain a comma-separated
list of nodes, to handle MIBs like this.
cpu_pstat.c: fix missing break(s) in switch statement
BUG #a2551: fix non-sequential cpu numbers on HP-UX.
Thanks to Dave Olker.
HP UX, CPU statistics: Fix an invalid pointer dereference

See also commit 0034581deb3e676d328824c87637aaca31850c6a.
Merge branch 'V5-4-patches' of ssh://git.code.sf.net/p/net-snmp/code into V5-4-patches
AIX: Fix a few compiler warnings

Avoid that the following compiler warnings are reported:
- Assignment discards const.
- Unused local variable.
- Mismatch between format string and argument list.

Also correct the indentation of two Solaris-specific code statements.
Remove C99 length specifier 'z' and use a cast instead

See also commit b4eab11139eb122c9ad3c13ab8b9453e04e46842.
If the asp lookup returns NULL, don't try to use it

If there is no corresponding asp, we set the result properly
but still fall through and attempt to use it.  Instead, just
continue.
snmpnetstat/if.c: properly detect snmp exceptions