Description:
When compiling libcap 2.63-3 with linux headers >2.6.29, compile fails due to changes in the capabilites header file. The error message can be seen below:

gcc -O2 -Dlinux -fPIC -Wall -Wwrite-strings -Wpointer-arith -Wcast-qual -Wcast-align -Wstrict-prototypes -Wmiss
ing-prototypes -Wnested-externs -Winline -Wshadow -g -I/home/build/abs/core/libcap/src/libcap-2.16/progs/../li
bcap/include -I/home/build/abs/core/libcap/src/libcap-2.16/progs/../libcap/include -c setcap.c -o setcap.o
In file included from /usr/include/bits/sigcontext.h:29,
from /usr/include/signal.h:340,
from /usr/include/sys/wait.h:32,
from capsh.c:20:
/usr/include/asm/sigcontext.h:28: error: expected specifier-qualifier-list before ‘__u64’
In file included from /usr/include/bits/sigcontext.h:29,
from /usr/include/signal.h:340,
from /usr/include/sys/wait.h:32,
from capsh.c:20:
/usr/include/asm/sigcontext.h:191: error: expected specifier-qualifier-list before ‘__u64’
make[1]: *** [capsh.o] Error 1
make[1]: *** Waiting for unfinished jobs....
make[1]: Leaving directory `/home/build/abs/core/libcap/src/libcap-2.16/progs'
make: *** [install] Error 2

There is a bugreport and working patch at http://bugs.gentoo.org/265304.
I've attached a working PKGBUILD + Patch. Note, that I have only been able to test this on i686, no idea if the patch works fine on 64bit. Also note that it took a while to spot the error, due to missing "|| return 1", I added that to the PKGBUILD as well.