Added a (obvious, in retrospect) additional automatic handling of

nets to be avoided for running antenna gate and diffusion area
checks when doing "lef write", which is to check if the pin of
the net is flagged with use "power" or use "ground".  This avoids
the need to use the (recently added) "lef nocheck" option (although
that still exists as an additional way to control which nets do and
do not get checked).

doc/html/lef.html

@@ -76,6 +76,18 @@ LEF-format input and output
 		itself would be written to a DEF file. <BR>
 		Options <B>-hide</B>, <B>-tech</B>, and <B>-toplayer</B> are
 		the same as for the <B>lef write</B> command.
+	   <DT> <B>nocheck</B> [<I>netname</I> ...]|[<B>none</B>]
+	   <DD> Do not check for antenna diffusion and gate area on the nets with
+		the names given as option <I>netname</I>.
+		Any number of net names may be given as arguments.  Typically,
+		power and ground nets should not need these checks.  If the nets
+		are attached to port labels that have been flagged with the use
+		"<B>power</B>" or "<B>ground</B>", then these nets will be
+		skipped automatically.  If not, then this command option provides
+		an alternative way to avoid running the checks, which can cause
+		a huge performance hit when generating a LEF view of a large
+		layout.  With the single argument "<B>none</B>", removes the
+		list of net names for which antenna checks should be skipped.
 	   <DT> <B>datestamp</B> [<I>value</I>|<B>default</B>]
 	   <DD> Force all cell definitions generated from LEF macros to have
 		the datestamp (timestamp) of <I>value</I>.  This can be used to