Define HAVE_STRERROR.
diff --git a/PC/config.h b/PC/config.h
index ceac9a0..0bc8cc5 100644
--- a/PC/config.h
+++ b/PC/config.h
@@ -72,6 +72,7 @@
 #include <stdio.h>
 #define HAVE_CLOCK
 #define HAVE_STRFTIME
+#define HAVE_STRERROR
 #define NT_THREADS
 #define WITH_THREAD
 #ifndef NETSCAPE_PI