2.1b6 build problems

[Frank Solensky <solensky@TopLayer.com>]

I didn't see these on the "ns problems" web page, so consider them reported:

Host system is running Red Hat 6.1 (aka Linux 2.2-12.20), Pentium II
processor.

1) ./configure
	Running the script with no additional command line options fails.  The last
couple lines of output are:

d is 
checking for tclsh8.0.4... no
checking for tclsh8.0... /usr/bin/tclsh8.0
checking for tk.h... configure: error: NONE is not a directory

	Running with "--with-tk" works ("d" is still null, FWIW).

	The problem did not occur with the 2.1b5 distribution.

2) make install:  an INSTALL variable must be explicitly set on the command
line (ie: 'make INSTALL="/usr/bin/install -c"')

	Output without the argument:

	for i in indep-utils/cmu-scen-gen/setdest indep-utils/webtrace-conv/dec
indep-utils/webtrace-conv/epa indep-utils/webtrace-conv/nlanr
indep-utils/webtrace-conv/ucb; do cd $i; make install; done
make[1]: Entering directory
`/free_sw/ns-2.1b6/indep-utils/cmu-scen-gen/setdest'
m 555 -o bin -g bin setdest /usr/local/bin
make[1]: m: Command not found
make[1]: [install] Error 127 (ignored)