dejagnu runtest and runtest.exp

[meissner@cygnus.com]

| > Philippe De Muyter just posted a patch
| > (< 199710131730.TAA11370@mail.macqel.be >) which should fix that, but I
| > think his patch should be changed to search PATH rather than to rely
| > on the builtin ``type'' command.
| 
| OK, here it is.  With an example it is much easier :)
| Note that I use test -x, not -f as in example Ian provided.  This should
| perhaps be fixed in configure.

If this code is going to run on really old shells, then please change the test
back to -f, as I recall, the older shells on systems such as BSD 4.2 and Ultrix
did not support the full range of test features.