#10 avoid tampering with TMPDIR

[Michael Shigorin]

Please consider changing TMDIR to something like TEMPDIR as overriding this particular variable can be both a security risk in a scenario when Bob desperately wants to mess up Alice's ipmiutil build with TMPDIR set to /tmp, and in my case a compiler (lcc 1.23/1.24, not gcc but rather similar to icc in general) gets confused over its own temporary files being missing in that prefix.
The problem is present in the current 3.1.6 release as well.
Quick workaround: sed -i 's,TMPDIR,TEMDIR,g' Makefile*
Thank you for the tool!