archival: avoid std namespace for local includes

Avoid using same include file naming pattern as available in GLIBC.
Renamed to match grp_.h et al.

Signed-off-by: Joachim Nilsson <troglobit@gmail.com>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

archival/ar.c

@@ -60,7 +60,7 @@
 
 #include "libbb.h"
 #include "bb_archive.h"
-#include "ar.h"
+#include "ar_.h"
 
 #if ENABLE_FEATURE_AR_CREATE
 /* filter out entries with same names as specified on the command line */

archival/libarchive/get_header_ar.c

@@ -6,7 +6,7 @@
  */
 #include "libbb.h"
 #include "bb_archive.h"
-#include "ar.h"
+#include "ar_.h"
 
 /* WARNING: Clobbers str[len], so fields must be read in reverse order! */
 static unsigned read_num(char *str, int base, int len)

archival/libarchive/unpack_ar_archive.c

@@ -4,7 +4,7 @@
  */
 #include "libbb.h"
 #include "bb_archive.h"
-#include "ar.h"
+#include "ar_.h"
 
 void FAST_FUNC unpack_ar_archive(archive_handle_t *ar_archive)
 {