test/Makefile: Support non-GNU sed

This required two changes:

    1. Modifying a file inplace using -i is not portable. GNU sed does
       not require an argument; the absence of it meaning it should
       change the file inplace. sed found on FreeBSD and probably other
       BSDs' require an argument, so inplace modification should be
       specified as: sed -i ''. Obviously, both -i are incompatible...
       The "solution" is to specify a backup suffix and ignore this
       backup file.

    2. The [1addr]i command takes its argument on the next line
       according to the standard (though, it's not explicitely stated,
       the syntax example suggests that). GNU sed accepts to have its
       argument on the same line as the command, but not FreeBSD's sed.

0 files changed, 0 insertions, 0 deletions