Comment 1 for bug 1097560

This fails to build on raring, log snippet below and full log attached:

x86_64-linux-gnu-gcc -DHAVE_CONFIG_H -I. -I.. -D_FORTIFY_SOURCE=2 -DBYZANZ_MENU_UI_DIR=\""/usr/share/byzanz"\" -pthread -I/usr/include/glib-2.0 -I/usr/lib/x86_64-linux-gnu/glib-2.0/include -I/usr/include/gconf/2 -I/usr/include/gtk-3.0 -I/usr/include/dbus-1.0 -I/usr/lib/x86_64-linux-gnu/dbus-1.0/include -I/usr/include/atk-1.0 -I/usr/include/at-spi2-atk/2.0 -I/usr/include/pango-1.0 -I/usr/include/gio-unix-2.0/ -I/usr/include/cairo -I/usr/include/gdk-pixbuf-2.0 -I/usr/include/freetype2 -I/usr/include/pixman-1 -I/usr/include/libpng12 -I/usr/include/gnome-panel-4.0/libpanel-applet -pthread -I/usr/include/cairo -I/usr/include/glib-2.0 -I/usr/lib/x86_64-linux-gnu/glib-2.0/include -I/usr/include/pixman-1 -I/usr/include/freetype2 -I/usr/include/libpng12 -I/usr/include/gtk-3.0 -I/usr/include/atk-1.0 -I/usr/include/at-spi2-atk/2.0 -I/usr/include/pango-1.0 -I/usr/include/gio-unix-2.0/ -I/usr/include/gdk-pixbuf-2.0 -pthread -I/usr/include/gstreamer-0.10 -I/usr/include/glib-2.0 -I/usr/lib/x86_64-linux-gnu/glib-2.0/include -I/usr/include/libxml2 -Wall -Wextra -Wno-missing-field-initializers -Wno-unused-parameter -Wold-style-definition -Wdeclaration-after-statement -Wmissing-declarations -Wmissing-prototypes -Wredundant-decls -Wmissing-noreturn -Wshadow -Wpointer-arith -Wwrite-strings -Winline -Wformat-nonliteral -Wformat-security -Wswitch-enum -Wswitch-default -Winit-self -Wmissing-include-dirs -Wundef -Waggregate-return -Wmissing-format-attribute -Wnested-externs -Wunsafe-loop-optimizations -Wpacked -Winvalid-pch -Wsync-nand -Werror -g -O2 -fPIE -fstack-protector --param=ssp-buffer-size=4 -Wformat -Werror=format-security -MT byzanz_applet-byzanzapplet.o -MD -MP -MF .deps/byzanz_applet-byzanzapplet.Tpo -c -o byzanz_applet-byzanzapplet.o `test -f 'byzanzapplet.c' || echo './'`byzanzapplet.c
byzanzapplet.c: In function 'main':
byzanzapplet.c:438:1: error: implicit declaration of function 'unsetenv' [-Werror=implicit-function-declaration]
byzanzapplet.c:438:1: error: nested extern declaration of 'unsetenv' [-Werror=nested-externs]
cc1: all warnings being treated as errors
make[4]: *** [byzanz_applet-byzanzapplet.o] Error 1
make[4]: Leaving directory `/«BUILDDIR»/byzanz-0.3.0+git20120930/src'
make[3]: *** [all] Error 2
make[3]: Leaving directory `/«BUILDDIR»/byzanz-0.3.0+git20120930/src'
make[2]: *** [all-recursive] Error 1
make[2]: Leaving directory `/«BUILDDIR»/byzanz-0.3.0+git20120930'
make[1]: *** [all] Error 2
make[1]: Leaving directory `/«BUILDDIR»/byzanz-0.3.0+git20120930'
dh_auto_build: make -j1 returned exit code 2
make: *** [build-arch] Error 2
dpkg-buildpackage: error: debian/rules build-arch gave error exit status 2
Sessions still open, not unmounting