core: add bitop implementations for darwin and linux

core/sys/linux/bitop.c

@@ -0,0 +1,16 @@
+#include <blue/core/bitop.h>
+
+int b_popcountl(long v)
+{
+	return __builtin_popcountl(v);
+}
+
+int b_ctzl(long v)
+{
+	return __builtin_ctzl(v);
+}
+
+int b_clzl(long v)
+{
+	return __builtin_clzl(v);
+}