diff --git a/lib/defines.h b/lib/defines.h
index 6b1bb3cb..316cce5a 100644
--- a/lib/defines.h
+++ b/lib/defines.h
@@ -22,8 +22,6 @@ typedef unsigned char _Bool;
 # define __bool_true_false_are_defined 1
 #endif
 
-#define ISDIGIT_LOCALE(c) isdigit (c)
-
 /* Take care of NLS matters.  */
 #ifdef S_SPLINT_S
 extern char *setlocale(int categories, const char *locale);
diff --git a/libmisc/getdate.y b/libmisc/getdate.y
index 4d282edc..82f1369c 100644
--- a/libmisc/getdate.y
+++ b/libmisc/getdate.y
@@ -31,14 +31,11 @@
 #include <ctype.h>
 #include <time.h>
 
-#define ISDIGIT_LOCALE(c) isdigit (c)
-
-/* ISDIGIT differs from ISDIGIT_LOCALE, as follows:
+/* ISDIGIT differs from isdigit(3), as follows:
    - Its arg may be any int or unsigned int; it need not be an unsigned char.
-   - It's guaranteed to evaluate its argument exactly once.
    - It's typically faster.
    Posix 1003.2-1992 section 2.5.2.1 page 50 lines 1556-1558 says that
-   only '0' through '9' are digits.  Prefer ISDIGIT to ISDIGIT_LOCALE unless
+   only '0' through '9' are digits.  Prefer ISDIGIT to isdigit(3) unless
    it's important to use the locale's definition of `digit' even when the
    host does not conform to Posix.  */
 #define ISDIGIT(c) ((unsigned) (c) - '0' <= 9)