Initialize inc_fibnum for properly handling ICMP6_PACKET_TOO_BIG errors
in multifib environment.

PR:		183265
MFC after:	1 week
Queisce quite a few clang warnings -Wdangling-else due to this work around
for compiling gperf under Visual Studio from 1998.

ref. http://msdn.microsoft.com/en-us/library/b80153d8%28v=vs.90%29.aspx
ref. http://stackoverflow.com/questions/984878/what-is-the-possible-use-for-define-for-if-false-else-for