1 files changed, 2 insertions, 1 deletions
diff --git a/src/tr.c b/src/tr.c
index a1376381d..f30fa9cb6 100644
--- a/src/tr.c
+++ b/src/tr.c
@@ -15,8 +15,9 @@
    along with this program; if not, write to the Free Software
    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.  */
 
-/* Written by Jim Meyering. */
+/* Written by Jim Meyering, meyering@cs.utexas.edu. */
 
+/* Get isblank from GNU libc.  */
 #define _GNU_SOURCE
 #include <ctype.h>
 #ifndef isblank