diff -up chemtool-1.6.12/src-cht/cht-2.5.c.compile chemtool-1.6.12/src-cht/cht-2.5.c
--- chemtool-1.6.12/src-cht/cht-2.5.c.compile	2007-11-10 22:12:35.000000000 +0100
+++ chemtool-1.6.12/src-cht/cht-2.5.c	2009-08-22 13:49:26.000000000 +0200
@@ -121,11 +121,6 @@
 #define LACK_MEMMOVE
 #define LACK_MEMCPY
 
-#else
-
-#define LACK_LABS       /* Undefine these if your library has these */
-#define LACK_MEMMOVE
-
 #endif
 #endif
 
@@ -593,13 +588,15 @@ char **argv;
 
 /* In case your system lacks these... */
 
+#ifdef LACK_LABS
 long my_labs(x)
 long x;
 {
     return((x > 0) ? x : -x);
 }
+#endif /* LACK_LABS */
 
-
+#ifdef LACK_MEMMOVE
 #ifdef __STDC__
 Anyptr my_memmove(Anyptr d, Const Anyptr s, size_t n)
 #else
@@ -623,8 +620,9 @@ register int n;
     }
     return d;
 }
+#endif /* LACK_MEMMOVE */
 
-
+#ifdef LACK_MEMCPY
 #ifdef __STDC__
 Anyptr my_memcpy(Anyptr d, Const Anyptr s, size_t n)
 #else
@@ -638,7 +636,9 @@ register int n;
 	*dd++ = *ss++;
     return d;
 }
+#endif /* LACK_MEMCPY */
 
+#ifdef LACK_MEMCMP
 #ifdef __STDC__
 int my_memcmp(Const Anyptr s1, Const Anyptr s2, size_t n)
 #else
@@ -654,7 +654,9 @@ register int n;
 	    return i;
     return 0;
 }
+#endif /* LACK_MEMCMP */
 
+#ifdef LACK_MEMSET
 #ifdef __STDC__
 Anyptr my_memset(Anyptr d, int c, size_t n)
 #else
@@ -669,7 +671,7 @@ register int n;
 	*dd++ = c;
     return d;
 }
-
+#endif /* LACK_MEMSET */
 
 int my_toupper(c)
 int c;