automake-1.4-p2 DOS platform bug

[Bruno Haible]

To reproduce:
- take gettext-0.10.38,
- remove the configure.in lines 111 to 135 (which contain a workaround to this
  bug)
- run "./aclocal.sh aclocal -I m4"
- run "automake --gnits --include-deps Makefile misc/Makefile tests/Makefile"
- run "autoconf" (from autoconf-2.13)

Then in tests/Makefile.in the EXTRA_PROGRAMS will not have $(EXEEXT) added,
unlike the treatment of the bin_PROGRAMS. On DOS/DJGPP platforms, where
$(EXEEXT) is nonempty: all-local depends on tstgettext, but there is no
rule for tstgettext, only for tstgettext$(EXEEXT). This leads to a "make"
failure.

A fix that works for me is to rewrite Makefile.in line

   EXTRA_PROGRAMS = tstgettext tstngettext cake

to

   EXTRA_PROGRAMS = tstgettext$(EXEEXT) tstngettext$(EXEEXT) cake$(EXEEXT)

Bruno