[PATCH v2] text-utils/hexsyntax.c: fix for missing program_invocation_short_name

["Andreas Bießmann" <biessmann@corscience.de>]

Some libc do not expose program_invocation_short_name. Therefore util-linux
comes with helpers in 'c.h'. Use the 'c.h' in hexsyntax.c where it was missed.

This patch fixes following error for me:
---8<---
hexsyntax.c: In function 'newsyntax':
hexsyntax.c:115: error: 'program_invocation_short_name' undeclared (first use in this function)
hexsyntax.c:115: error: (Each undeclared identifier is reported only once
hexsyntax.c:115: error: for each function it appears in.)
--->8---

Signed-off-by: Andreas Bießmann <biessmann@corscience.de>
---
since v1:
 clearify commit message

 text-utils/hexsyntax.c |    1 +
 1 file changed, 1 insertion(+)

diff --git a/text-utils/hexsyntax.c b/text-utils/hexsyntax.c
index 5f3b733..21cc55e 100644
--- a/text-utils/hexsyntax.c
+++ b/text-utils/hexsyntax.c
@@ -45,6 +45,7 @@
 #include "hexdump.h"
 #include "nls.h"
 #include "strutils.h"
+#include "c.h"
 
 off_t skip;				/* bytes to skip */
 
-- 
1.7.10