diff --git a/src/macros.h b/src/macros.h
index 0794644657afeb416fb1c5bd8b081c5b98f260de..d26d5f6f30b18b59816563bd9be10cbef277dd36 100644
--- a/src/macros.h
+++ b/src/macros.h
@@ -19,7 +19,7 @@
 #define MAXIMUM(X,Y) ((X)>(Y)?(X):(Y))
 
 
-#define is8bitalnum(X)	("0000000000000000000000000000100000000000000000000111111111000000011111111111111111111111111000010111111111111111111111111110000000000000000000000000000000000000101111010110001011110110011011100000000001111111111111101111111111111111111111111111111011111111"[((unsigned)X)&0xff] == '1')
+#define is8bitalnum(X)	("0000000000000000000000000000100000000000000000000111111111000000011111111111111111111111111000010111111111111111111111111110000000000000000000000000000000000000101111010110001011110110011011100000000001111111111111101111111111111111111111111111111011111111"[((unsigned)(X))&0xff] == '1')
   
 #define isidchar(X) is8bitalnum(X)