klee/0001-errno-define-__errno_location.patch

From: Jiri Slaby <jirislaby@gmail.com>
Date: Fri, 17 Mar 2017 13:15:18 +0100
Subject: errno: define __errno_location
Patch-mainline: no

POSIX runtime library is built on my system with a reference to
__errno_location(). And then it is undefined when klee is run
--with-posix:
KLEE: NOTE: Using model: lib/libkleeRuntimePOSIX.bca
KLEE: output directory is "test/Runtime/POSIX/Output/Read1.c.tmp.klee-out"
KLEE: Using STP solver backend
KLEE: WARNING: undefined reference to function: __errno_location
KLEE: WARNING ONCE: calling external: __errno_location()
KLEE: ERROR: (location information missing) ASSERTION FAIL: x == -1 && errno == EFAULT
KLEE: NOTE: now ignoring this error at this location
EXITING ON ERROR:
Error: ASSERTION FAIL: x == -1 && errno == EFAULT
Stack:
       #000000170 in main (argc=4, argv=24928704)

Therefore, the tests fail.

Define __errno_location as a weak symbol to return the actual int errno.

Signed-off-by: Jiri Slaby <jirislaby@gmail.com>
---
 runtime/POSIX/errno_location.c |    9 +++++++++
 1 file changed, 9 insertions(+)
 create mode 100644 runtime/POSIX/errno_location.c

--- /dev/null
+++ b/runtime/POSIX/errno_location.c
@@ -0,0 +1,9 @@
+#include <errno.h>
+
+#undef errno
+int errno __attribute__((weak));
+
+int __attribute__((weak)) *__errno_location(void)
+{
+	return &errno;
+}