pixman: add patch to fix SEGFAULT when parsing auxv

* without this patch emacs won't build
* temacs is executed in qemu and fails like this:
qemu: uncaught target signal 11 (Segmentation fault) - core dumped
Segmentation fault
which is actually:
Program received signal SIGSEGV, Segmentation fault.
__GI_strncmp (s1=s1@entry=0x0, s2=s2@entry=0x40d68638 "v7l", n=n@entry=3) at strncmp.c:64
64      strncmp.c: No such file or directory.
(gdb) bt
Backtrace stopped: previous frame identical to this frame (corrupt stack?)

Signed-off-by: Martin Jansa <Martin.Jansa@gmail.com>