doc: refactor description of color format

diff --git a/ewah/ewok.h b/ewah/ewok.h
index f6ad190a038a55e39a0b8b135c995413192f80e3..16b7a795a0619fef02afb55f849dbedde2896c8f 100644 (file)
--- a/ewah/ewok.h
+++ b/ewah/ewok.h
@@ -31,7 +31,7 @@
 #endif
 
 typedef uint64_t eword_t;
-#define BITS_IN_WORD (sizeof(eword_t) * 8)
+#define BITS_IN_EWORD (sizeof(eword_t) * 8)
 
 /**
  * Do not use __builtin_popcountll. The GCC implementation
@@ -47,7 +47,8 @@ static inline uint32_t ewah_bit_popcount64(uint64_t x)
        return (x * 0x0101010101010101ULL) >> 56;
 }
 
-#ifdef __GNUC__
+/* __builtin_ctzll was not available until 3.4.0 */
+#if defined(__GNUC__) && (__GNUC__ > 3 || (__GNUC__ == 3  && __GNUC_MINOR > 3))
 #define ewah_bit_ctz64(x) __builtin_ctzll(x)
 #else
 static inline int ewah_bit_ctz64(uint64_t x)