[PATCH] build: avoid build failure without sys/mtio.h

[Pádraig Brady]

* m4/jm-macros.m4: Check for the header.
* src/dd.c: Avoid the workaround where the header
is not available (on non glibc systems).
---
 m4/jm-macros.m4 | 1 +
 src/dd.c        | 2 +-
 2 files changed, 2 insertions(+), 1 deletion(-)

diff --git a/m4/jm-macros.m4 b/m4/jm-macros.m4
index 399f69b..5aef4ba 100644
--- a/m4/jm-macros.m4
+++ b/m4/jm-macros.m4
@@ -211,6 +211,7 @@ AC_DEFUN([gl_CHECK_ALL_HEADERS],
     paths.h
     priv.h
     stropts.h
+    sys/mtio.h
     sys/param.h
     sys/systeminfo.h
     syslog.h
diff --git a/src/dd.c b/src/dd.c
index 7b3d2fd..7898116 100644
--- a/src/dd.c
+++ b/src/dd.c
@@ -1720,7 +1720,7 @@ advance_input_offset (uintmax_t offset)
    The offending behavior has been confirmed with an Exabyte SCSI tape
    drive accessed via /dev/nst0 on both Linux 2.2.17 and 2.4.16 kernels.  */
 
-#ifdef __linux__
+#if defined __linux__ && HAVE_SYS_MTIO_H
 
 # include <sys/mtio.h>
 
-- 
2.9.3