libtool can't build libgpgme.a 0.3.9 under CygWin 1.3.12

[Dr.Stefan.Dalibor at bfa.de]

Hi,
I have problems building gpgme 0.3.9 under CygWin 1.3.12 - the build
process stops when trying to link libgpgme.a in the gpgme
subdirectory:

...
/bin/bash ../libtool --mode=link gcc  -O2 -Wall -Wcast-align -Wshadow -Wstrict-prototypes   -o libgpgme.la -rpath /usr/local/lib -version-info 9:0:3
util.lo dat
a.lo recipient.lo signers.lo wait.lo op-support.lo encrypt.lo encrypt-sign.lo decrypt.lo decrypt-verify.lo verify.lo sign.lo passphrase.lo progress.lo
 key.lo ke
ylist.lo trustlist.lo import.lo export.lo genkey.lo delete.lo edit.lo rungpg.lo engine-gpgsm.lo engine.lo ath.lo ath-pthread.lo  posix-util.lo
posix-sema.lo posix-io.lo debug.lo gpgme.lo version.lo errors.lo   stpcpy.o vasprintf.o fopencookie.o
mkdir .libs
libtool: link: cannot build libtool library `libgpgme.la' from non-libtool objects on this host: stpcpy.o vasprintf.o fopencookie.o
make[3]: *** [libgpgme.la] Error 1
make[3]: Leaving directory `/tmp/gpgme-0.3.9/cygwin/gpgme'
...

It seems that the supplementary modules gpgme needs (vasprintf etc.,
determined by configure) are not getting the right libtool treatment:
there are no .lo files for these modules, they are built by the C
compiler (instead by `libtool --mode=compile' as the other gpgme
modules) and so on.

Configuring gpgme with option `--enable-shared=no' doesn't help, but
either editing
o libtool - set variable `deplibs_check_method' to `pass_all'
o or gpgme/Makefile - change filename extension for the supplementary
  modules from `.o' to `.lo' in the line starting with
  `libgpgme_la_LIBADD ='
produces a working (i.e. passing all self-tests) libgpgme.a.

Cheers,
Stefan