parallel build fails

If I drop -j8, it works.
It seems make is called in parallel with quilt and configure.

$ dpkg-buildpackage -us -uc -b -j8
dpkg-buildpackage: export CFLAGS from dpkg-buildflags (origin: vendor): -g -O2
dpkg-buildpackage: export CPPFLAGS from dpkg-buildflags (origin: vendor):
dpkg-buildpackage: export CXXFLAGS from dpkg-buildflags (origin: vendor): -g -O2
dpkg-buildpackage: export FFLAGS from dpkg-buildflags (origin: vendor): -g -O2
dpkg-buildpackage: export LDFLAGS from dpkg-buildflags (origin: vendor): -Wl,-Bsymbolic-functions
dpkg-buildpackage: source package nspluginwrapper
dpkg-buildpackage: source version 1.4.2-0ubuntu3
dpkg-buildpackage: source changed by Marc Deslauriers <email address hidden>
 dpkg-source --before-build nspluginwrapper-1.4.2
dpkg-buildpackage: host architecture amd64
 fakeroot debian/rules clean
dh_testdir
QUILT_PATCHES=debian/patches \
  quilt --quiltrc /dev/null pop -a -R || test $? = 2
No patch removed
rm -rf .pc debian/stamp-patched
dh_testroot
rm -f build-stamp configure-stamp
[ ! -f Makefile ] || /usr/bin/make distclean
make[1]: Entering directory `/tmp/nspluginwrapper-1.4.2'
rm -f npconfig npviewer.sh npwrapper.so test-rpc-types-client test-rpc-nested-1-client test-rpc-nested-2-client test-rpc-concurrent-client test-rpc-types-server test-rpc-nested-1-server test-rpc-nested-2-server test-rpc-concurrent-server *.o *.os
rm -rf lsb-build-
rm -f config-host.* config.*
make[1]: Leaving directory `/tmp/nspluginwrapper-1.4.2'
dh_clean
 debian/rules build
dh_testdir
dh_testdir
QUILT_PATCHES=debian/patches \
  quilt --quiltrc /dev/null push -a || test $? = 2
/usr/bin/make
make[1]: Entering directory `/tmp/nspluginwrapper-1.4.2'
cc -Wall -g -O2 -o npconfig-npw-config.o -c src/npw-config.c -I. -I.
sed -e 's|%NPW_VIEWER_DIR%||' src/npw-viewer.sh > npviewer.sh
cc -o npwrapper-npw-wrapper.os -c src/npw-wrapper.c -fPIC -I. -I. -Wall -g -O2 -I./npapi -DBUILD_WRAPPER
cc -o npwrapper-npw-common.os -c src/npw-common.c -fPIC -I. -I. -Wall -g -O2 -I./npapi -DBUILD_WRAPPER
./configure --prefix=/usr --with-lib32=lib32 --with-lib64=lib --enable-biarch
cc -o npwrapper-npw-malloc.os -c src/npw-malloc.c -fPIC -I. -I. -Wall -g -O2 -I./npapi -DBUILD_WRAPPER
chmod 755 npviewer.sh
cc -o npwrapper-npw-rpc.os -c src/npw-rpc.c -fPIC -I. -I. -Wall -g -O2 -I./npapi -DBUILD_WRAPPER
cc -o npwrapper-rpc.os -c src/rpc.c -fPIC -I. -I. -Wall -g -O2 -I./npapi -DBUILD_WRAPPER
In file included from src/npw-wrapper.c:23:0:
src/sysdeps.h:26:2: error: #error "Your compiler is not ISO. Get a real one."
src/sysdeps.h:30:20: fatal error: config.h: No such file or directory
compilation terminated.
make[1]: *** [npwrapper-npw-wrapper.os] Error 1
make[1]: *** Waiting for unfinished jobs....
In file included from src/npw-config.c:21:0:
src/sysdeps.h:26:2: error: #error "Your compiler is not ISO. Get a real one."
src/sysdeps.h:30:20: fatal error: config.h: No such file or directory
compilation terminated.
In file included from src/npw-common.c:21:0:
src/sysdeps.h:26:2: error: #error "Your compiler is not ISO. Get a real one."
src/sysdeps.h:30:20: fatal error: config.h: No such file or directory
compilation terminated.
make[1]: *** [npconfig-npw-config.o] Error 1
make[1]: *** [npwrapper-npw-common.os] Error 1
In file included from src/npw-rpc.c:21:0:
src/sysdeps.h:26:2: error: #error "Your compiler is not ISO. Get a real one."
src/sysdeps.h:30:20: fatal error: config.h: No such file or directory
compilation terminated.
In file included from src/rpc.c:30:0:
src/sysdeps.h:26:2: error: #error "Your compiler is not ISO. Get a real one."make[1]: *** [npwrapper-npw-rpc.os] Error 1

src/sysdeps.h:30:20: fatal error: config.h: No such file or directory
compilation terminated.
make[1]: *** [npwrapper-rpc.os] Error 1
In file included from src/npw-malloc.c:21:0:
src/sysdeps.h:26:2: error: #error "Your compiler is not ISO. Get a real one."
src/sysdeps.h:30:20: fatal error: config.h: No such file or directory
compilation terminated.
make[1]: *** [npwrapper-npw-malloc.os] Error 1
make[1]: Leaving directory `/tmp/nspluginwrapper-1.4.2'
make: *** [build-stamp] Error 2
make: *** Waiting for unfinished jobs....
Applying patch 000_debian_make_symlinks.diff
patching file src/npw-config.c

Applying patch 002_install_to_NSPLUGINDIR.diff
patching file src/npw-config.c

Applying patch 005_process_env_dirs.diff
patching file src/npw-config.c

Applying patch 006_flash_csw_workaround.diff
patching file Makefile

Now at patch 006_flash_csw_workaround.diff
touch debian/stamp-patched
Source path /tmp/nspluginwrapper-1.4.2
Install prefix /usr
nspluginwrapper root dir /usr/lib/nspluginwrapper
Viewer paths /usr/lib/nspluginwrapper/%ARCH%/%OS%
Build viewer yes
Build standalone player yes
Build 32-/64-bit at once yes
Build with generic APIs no
32-bit library dir name lib32
64-bit library dir name lib
C compiler gcc -std=c99
C++ compiler g++
Strip binaries no
Host OS linux
Host CPU x86_64
Host big endian no
Target OS linux
Target CPU i386
RPC init timeout 5 secs
Memory allocation hooks glib libc
Use thread checks (DEBUG) no
Use malloc checks (DEBUG) no
touch configure-stamp
dpkg-buildpackage: error: debian/rules build gave error exit status 2