bug#25335: automake - dejagnu RUNTESTDEFAULTFLAGS overrides AM_RUNTESTFLAGS

[Carnë Draug]

There are 3 variables used by automake when calling dejagnu's
runtest:

  $RUNTESTDEFAULTFLAGS - default from automake
  $AM_RUNTESTFLAGS - set by package developer
  $RUNTESTFLAGS - for user configuration

However, AM_RUNTESTFLAGS is used first and is therefore overwritten
by RUNTESTDEFAULTFLAGS.  My use case is that I am not using recursive
make and therefore want to set dejagnu's srcdir to the testsuite
directory.  But RUNTESTDEFAULTFLAGS then sets it to $srcdir. Here's
the lines causing my issue:

RUNTESTDEFAULTFLAGS = --tool $$tool --srcdir $$srcdir
[...]
        if $(RUNTEST) $(AM_RUNTESTFLAGS) $(RUNTESTDEFAULTFLAGS)
$(RUNTESTFLAGS); \
[...]

A possible fix is to swap their order (simple patch attached).

Another issue I am having with this is that the recipe to create the
site.exp file, also built by automake, sets dejagnu's srcdir to the
Makefile $srcdir again.  I am unsure how best to fix that (I guess a
maintainer variable).

Carnë