Bug#837670: ocaml-ctypes: FTBFS with bindnow and PIE enabled

[Balint Reczey <balint@balintreczey.hu>]

Source: ocaml-ctypes
Version: 0.7.0-1
Severity: important
User: balint@balintreczey.hu
Usertags: pie-bindnow-20160906
Justification: FTBFS on amd64 with extra hardening

Hi,

During a rebuild of all packages in sid, your package failed to build on
amd64 with patched GCC and dpkg.

The rebuild tested if packages are ready for a transition
enabling PIE and bindnow for amd64.

For more information about the changes to sid's dpkg and GCC please
visit:
 https://wiki.debian.org/Hardening/PIEByDefaultTransition

Relevant part (hopefully):
...
ocamlfind opt -shared -linkall -principal -short-paths  -package
compiler-libs   -o _build/ctypes-top.cmxs
_build/src/ctypes-top/ctypes_printers.cmx
_build/src/ctypes-top/install_ctypes_printers.cmx  -cclib -Wl,--no-as-needed
findlib: [WARNING] Interface topdirs.cmi occurs in several directories:
/usr/lib/ocaml, /usr/lib/ocaml/compiler-libs
The following required C libraries are missing: libffi.
Please install them and retry. If they are installed in a non-standard
location
or need special flags, set the environment variables <LIB>_CFLAGS and
<LIB>_LIBS
accordingly and retry.

 For example, if libffi is installed in /opt/local, you can type:

   export LIBFFI_CFLAGS=-I/opt/local/include
   export LIBFFI_LIBS=-L/opt/local/lib
Makefile:193: recipe for target 'test-libffi' failed
make[1]: *** [test-libffi] Error 1
make[1]: Leaving directory '/<<PKGBUILDDIR>>'
...

The full build log is available from:
 https://people.debian.org/~rbalint/build-logs/pie-bindnow-20160906/ocaml-ctypes_0.7.0-1_amd64.build.gz

Linking with libffi_pic.a would probably fix the problem.

Thanks,
Balint