gauche-c-wrapper: ftbfs with GCC-5

Imported from Debian bug http://bugs.debian.org/777861:

Package: src:gauche-c-wrapper
Version: 0.6.1-5
Severity: normal
Tags: sid stretch
User: <email address hidden>
Usertags: ftbfs-gcc-5

Please keep this issue open in the bug tracker for the package it
was filed for. If a fix in another package is required, please
file a bug for the other package (or clone), and add a block in this
package. Please keep the issue open until the package can be built in
a follow-up test rebuild.

The package fails to build in a test rebuild on at least amd64 with
gcc-5/g++-5, but succeeds to build with gcc-4.9/g++-4.9. The
severity of this report may be raised before the stretch release.

The full build log can be found at:
http://people.debian.org/~doko/logs/gcc5-20150205/gauche-c-wrapper_0.6.1-5_unstable_gcc5.log
The last lines of the build log are at the end of this report.

To build with GCC 5, either set CC=gcc-5 CXX=g++-5 explicitly,
or install the gcc, g++, gfortran, ... packages from experimental.

  apt-get -t experimental install g++

Common build failures are C11 as the default C mode, new warnings
resulting in build failures with -Werror turned on, or new/dropped
symbols in Debian symbols files. For other C/C++ related build failures
see the porting guide at http://gcc.gnu.org/gcc-5/porting_to.html

[...]
cd objc; make all
make[2]: Entering directory '/«PKGBUILDDIR»/objc'
make[2]: Nothing to be done for 'all'.
make[2]: Leaving directory '/«PKGBUILDDIR»/objc'
cd doc; make all
make[2]: Entering directory '/«PKGBUILDDIR»/doc'
make[2]: Nothing to be done for 'all'.
make[2]: Leaving directory '/«PKGBUILDDIR»/doc'
cd testsuite; make check
make[2]: Entering directory '/«PKGBUILDDIR»/testsuite'
gcc -c -fPIC -o ffitest.o ffitest.c
gcc -shared -o ffitest.so ffitest.o
gcc -c -fPIC -o fptr_array.o fptr_array.c
gcc -shared -o fptr_array.so fptr_array.o
gcc -c -fPIC -o gcc_extension.o gcc_extension.c
gcc -shared -o gcc_extension.so gcc_extension.o
/usr/bin/gosh -I../src -I../lib attr-test.scm >> test.log
Testing parse-attribute ... passed.
/usr/bin/gosh -I../src -I../lib ffitest.scm >> test.log
Testing c-wrapper (ffi) ... passed.
/usr/bin/gosh -I../src -I../lib ctypestest.scm >> test.log
Testing c-types ... passed.
/usr/bin/gosh -I../src -I../lib cwrappertest.scm >> test.log
Testing c-wrapper ... ././ffitest.h:828: #f
././ffitest.h:828: [bug] lost macro body (at token: *eoi*)
*** ERROR: [bug] lost macro body
Stack Trace:
_______________________________________
  0 (proc i o)
        At line 511 of "/usr/share/gauche-0.9/0.9.4/lib/gauche/process.scm"
  1 (let ((gcc-error #f)) (let-keywords* rest ((show-define? #t)) (cal
        At line 956 of "../lib/c-wrapper/c-parser.scm"
  2 (with-error-handler (lambda (e) (let ((e e)) (%guard-rec e e ((<me
        [unknown location]
  3 (parse-macro include-dirs headers options)
        At line 1159 of "../lib/c-wrapper/c-parser.scm"
  4 (trunk)
        At line 67 of "../lib/c-wrapper/c-parser.scm"
  5 (c-parse (if (list? include-dirs) include-dirs (list include-dirs)
        At line 105 of "../lib/c-wrapper.scm"
make[2]: *** [check-c] Error 70
Makefile:69: recipe for target 'check-c' failed
make[2]: Leaving directory '/«PKGBUILDDIR»/testsuite'
make[1]: *** [check] Error 2
Makefile:46: recipe for target 'check' failed
make[1]: Leaving directory '/«PKGBUILDDIR»'
dh_auto_test: make -j1 check returned exit code 2
make: *** [build-arch] Error 2
debian/rules:10: recipe for target 'build-arch' failed
dpkg-buildpackage: error: debian/rules build-arch gave error exit status 2