Also, clean up the way we find the output file. From the comment:

# Finding the sample output.  The filename is of the form
#
#   <test>.stdout[-<compiler>][-<version>][-<wordsize>][-<platform>]
#
# and we pick the most specific version available.  The <version> is
# the major version of the compiler (e.g. 6.8.2 would be "6.8").  For
# more fine-grained control use if_compiler_lt().

I'll update the wiki too.