Make setenv() return status

Currently, the setenv function does not return an error code.
This patch allows to test for errors.

Signed-off-by: Steve Falco <sfalco@harris.com>
diff --git a/include/common.h b/include/common.h
index 3190781..10b997e 100644
--- a/include/common.h
+++ b/include/common.h
@@ -243,9 +243,9 @@
 int	getenv_r     (char *name, char *buf, unsigned len);
 int	saveenv	     (void);
 #ifdef CONFIG_PPC		/* ARM version to be fixed! */
-void inline setenv   (char *, char *);
+int inline setenv   (char *, char *);
 #else
-void	setenv	     (char *, char *);
+int	setenv	     (char *, char *);
 #ifdef CONFIG_HAS_UID
 void	forceenv     (char *, char *);
 #endif