In the default case, we don't need to use the stack, we can save r7 with
ip register (that what does eglibc).
This allow to fix vfork data corruption
(see 3884bfe9661955543ce203c60f9225bbdf33f6bb), because vfork now don't
use the stack.
Add signalfd() call to bionic.
Adding the signalfd call was done in 3 steps:
- add signalfd4 system call (function name and syscall
number) to libc/SYSCALLS.TXT
- generate all necessary headers by calling
libc/tools/gensyscalls.py. This patch is adding
the generated files since the build system
does not call gensyscalls.py.
- create the signalfd wrapper in signalfd.cpp and add
the function prototype to sys/signalfd.h
(cherry-pick of 0c11611c11f4dc1b6d43587b72c3ccbe8c51a51c, modified to
work with older versions of GCC still in use on some branches.)
Change-Id: I4c6c3f12199559af8be63f93a5336851b7e63355
