maint: fix const correctness warnings with security_context_t

The security_context_t type was always an artificial separation
from a standard char* string, and various libselinux using code
assumed both were synonymous.  In addition, prior to libselinux 2.3
function declarations were incorrect wrt constness of this type.
Here we replace security_context_t with char*, and also
provide a wrapper function to cater for the const issue on
older libselinux.

* src/system.h (se_const): A new function to avoid and identify
the const issue on older libselinux.
* src/copy.c: s/security_context_t/char */.
* src/cp.c: Likewise.
* src/id.c: Likewise.
* src/install.c: Likewise.
* src/ls.c: Likewise.
* src/mkdir.c: Likewise.
* src/mkfifo.c: Likewise.
* src/mknod.c: Likewise.
* src/runcon.c: Likewise.
* src/selinux.c: Likewise.
* tests/cp/no-ctx.sh: Likewise.
* src/chcon.c: Likesize.

1 files changed, 2 insertions, 2 deletions

diff --git a/src/id.c b/src/id.c
index f46bb41b5..ccd1e879a 100644
--- a/src/id.c
+++ b/src/id.c
@@ -58,7 +58,7 @@ static bool ok = true;
 
 /* The SELinux context.  Start with a known invalid value so print_full_info
    knows when 'context' has not been set to a meaningful value.  */
-static security_context_t context = NULL;
+static char *context = NULL;
 
 static struct option const longopts[] =
 {
@@ -220,7 +220,7 @@ main (int argc, char **argv)
       /* Report failure only if --context (-Z) was explicitly requested.  */
       if ((selinux_enabled && getcon (&context) && just_context)
           || (smack_enabled
-              && smack_new_label_from_self ((char **) &context) < 0
+              && smack_new_label_from_self (&context) < 0
               && just_context))
         error (EXIT_FAILURE, 0, _("can't get process context"));
     }