diff --git a/src/internal.h b/src/internal.h
index 5895030415968d72200599e8a59bbf01ffc2d5a3..1760e3b69cb47004f7bf511bfbc8683a1e8ad5eb 100644
--- a/src/internal.h
+++ b/src/internal.h
@@ -75,6 +75,7 @@
 # define STRNEQLEN(a, b, n) (strncmp(a, b, n) != 0)
 # define STRCASENEQLEN(a, b, n) (c_strncasecmp(a, b, n) != 0)
 # define STRPREFIX(a, b) (strncmp(a, b, strlen(b)) == 0)
+# define STRCASEPREFIX(a, b) (c_strncasecmp(a, b, strlen(b)) == 0)
 # define STRSKIP(a, b) (STRPREFIX(a, b) ? (a) + strlen(b) : NULL)
 
 # define STREQ_NULLABLE(a, b) \