qemu: virtfs-proxy-helper: use setresuid and setresgid

The setfsuid and setfsgid system calls are obscure and they complicate
the error checking (that glibc's warn_unused_result "feature" forces
us to do).  Switch to the standard setresuid and setresgid functions.

Signed-off-by: Paolo Bonzini <pbonini@redhat.com
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
qemu: vnc-tls: Fix compilation with newer versions of GNU-TLS

In my installation of GNU-TLS (v3.0.23) the type
gnutls_anon_server_credentials is marked deprecated, so -Werror
breaks compilation.
Simply replacing it with the newer ..._t version fixed the compilation
on my machine (Slackware 14.0). I cannot tell how far back this "new"
type goes, at least the header file in RHEL 5.0 (v1.4.1) seems to have
it already. If someone finds a broken distribution, tell me and I
insert some compat code.

Signed-off-by: Andre Przywara <osp@andrep.de>
stp: Fix missing function return statements

Add return statement to non-void functions

Signed-off-by: Michael Contreras <michael@inetric.com>
s2e: Port to LLVM 3.2

Port S2E to LLVM/CLANG 3.2

Signed-off-by: Michael Contreras <michael@inetric.com>
s2e:qemu:configure Disable _FORTIFY_SOURCE

Disable _FORTIFY_SOURCE because it seems broken with this qemu and clang 3.2

Signed-off-by: Michael Contreras <michael@inetric.com>
Avoid some compiler warnings

Signed-off-by: Vitaly Chipounov <vitaly.chipounov@epfl.ch>
Makefile: fix builds with Address Sanitizer

Signed-off-by: Vitaly Chipounov <vitaly.chipounov@epfl.ch>
Makefile: allow specifying custom -march for clang

Useful to build and use S2E in VirtualBox, which does
not support AVX instructions, causing SIGILL.

Signed-off-by: Vitaly Chipounov <vitaly.chipounov@epfl.ch>