libtool, cygwin: static archives have duplicate .o's

[Charles Wilson]

So I was building automake-1.6.1 and ran its self tests, which uncovered 
 a bug in libtool (CVS 20020316).

Automake's pr300-ltlib test:
  Fails in 'make install-strip' because 'strip --strip-debug' on a
  static library goes berzerk when the library contains two copies
  of the same object file.  Due to a bug in libtool-20020316,
  the test statlib DOES contain two copies of "a.o":
    ar cru subdir/.libs/libb.a  .libs/a.o   a.o
  The fix is to correct libtool so that it doesn't include bot
  PIC and nonPIC object files...or to make 'strip.exe' tolerant
  of the problem.
    How strip fails: it unpacks the static archive into a
  temporary directory.  However, somehow during the process, because
  there are two files with the same name (pathnames are not
  preserved), the unpacked object file gets created without a
  security descriptor (CYGWIN=ntsec, using NTFS filesystem) --
  and "permission denied" to even 'ls' the file...
    I think the problem in libtool is here: line 4259 in
  ltmain.in (4758 in libtool):
    oldobjs="$oldobjs$old_deplibs $non_pic_objects"
  well, $non_pic_objects=a.o, but $oldobjs=.libs/a.o
  so both object files get ar'ed into the static lib.  I'm not sure
  what the problem is: should we prevent .libs/a.o (the PIC object)
  from getting added to $oldobjs, or should this line actually read:
    oldobjs="$non_pic_objects"
  and nothing else?  If the former, how??

--Chuck