utils: Move TEMP_FAILURE_RETRY reimplementation here

This will allow it to be used in more places.

Helps: https://github.com/containers/bubblewrap/issues/657
Signed-off-by: Simon McVittie <smcv@collabora.com>

bubblewrap.c

@@ -44,15 +44,6 @@
 #define CLONE_NEWCGROUP 0x02000000 /* New cgroup namespace */
 #endif
 
-#ifndef TEMP_FAILURE_RETRY
-#define TEMP_FAILURE_RETRY(expression) \
-  (__extension__                                                              \
-    ({ long int __result;                                                     \
-       do __result = (long int) (expression);                                 \
-       while (__result == -1L && errno == EINTR);                             \
-       __result; }))
-#endif
-
 /* We limit the size of a tmpfs to half the architecture's address space,
  * to avoid hitting arbitrary limits in the kernel.
  * For example, on at least one x86_64 machine, the actual limit seems to be

utils.h

@@ -46,6 +46,15 @@
 #define FALSE 0
 typedef int bool;
 
+#ifndef TEMP_FAILURE_RETRY
+#define TEMP_FAILURE_RETRY(expression) \
+  (__extension__                                                              \
+    ({ long int __result;                                                     \
+       do __result = (long int) (expression);                                 \
+       while (__result == -1L && errno == EINTR);                             \
+       __result; }))
+#endif
+
 #define PIPE_READ_END 0
 #define PIPE_WRITE_END 1