Fix handling of errno if external functions are invoked

If an external function in KLEE is invoked, it might update errno.
Previously, the errno specific variable in a state was only updated
if it was part of the executed instructions.
That opened up a timeframe that increased the likelihood of errno being
overwritten by another method call.

This patch fixes two issues:
* the errno of the KLEE process state is updated before the external
function call allowing to detect changes to it later on
* after the external call, the memory object of errno is directly
updated
with its new value, reducing the likelihood to be overwritten by
another
call

Additional features:
* Add support for `errno()` for Darwin as well.
* Simplified errno handling in POSIX layer

1 files changed, 1 insertions, 0 deletions

diff --git a/test/Runtime/POSIX/Ioctl.c b/test/Runtime/POSIX/Ioctl.c
index e8220276..f1caaf77 100644
--- a/test/Runtime/POSIX/Ioctl.c
+++ b/test/Runtime/POSIX/Ioctl.c
@@ -5,6 +5,7 @@
 #include <assert.h>
 #include <fcntl.h>
 #include <sys/stat.h>
+#include <sys/ioctl.h>
 #include <termios.h>
 #include <asm/ioctls.h>
 #include <errno.h>