Further clarifications of the #ifdef/#if/#elif/#endif style information, largely submitted by bde.  Return our exemption of the #ifdef lint comments since the exemption is intended to handle a particularly common current case without mandating change.  Improve language and spelling, and slightly clarify the notions associated specifically with #elif.
Further clarifications of the #ifdef/#if/#elif/#endif style information,
largely submitted by bde.  Return our exemption of the #ifdef lint
comments since the exemption is intended to handle a particularly
common current case without mandating change.  Improve language and
spelling, and slightly clarify the notions associated specifically
with #elif.

Obtained from:	bde

jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase