Mavericks doesn't like these, because it already includes strlcat and strlcpy somewhere.

gistfile1.c

diff --git a/src/strlcatu.h b/src/strlcatu.h
index 386f97a..a20f2dd 100644
--- a/src/strlcatu.h
+++ b/src/strlcatu.h
@@ -21,6 +21,4 @@
 #ifndef __STRLCAT_H__
 #define __STRLCAT_H__
 
-size_t strlcat(char *, const char *, size_t);
-
 #endif /* __STRLCAT_H__ */
diff --git a/src/strlcpyu.h b/src/strlcpyu.h
index c400e5a..7b34b56 100644
--- a/src/strlcpyu.h
+++ b/src/strlcpyu.h
@@ -21,6 +21,4 @@
 #ifndef __STRLCPY_H__
 #define __STRLCPY_H__
 
-size_t strlcpy(char *, const char *, size_t);
-
 #endif /* __STRLCPY_H__ */