better includes?

libc/fltfmt.c

@@ -11,17 +11,10 @@
  * ANY REPRESENTATION OR WARRANTY OF ANY KIND CONCERNING THE MERCHANTABILITY
  * OF THIS SOFTWARE OR ITS FITNESS FOR ANY PARTICULAR PURPOSE.
  */
-#include <stdio.h>
-#include <math.h>
+#include <u.h>
+#include <libc.h>
 #include <float.h>
-#include <string.h>
-#include <stdlib.h>
-#include <errno.h>
-#include <stdarg.h>
 #include <ctype.h>
-#include <fmt.h>
-#include "plan9.h"
-#include "fmt.h"
 #include "fmtdef.h"
 
 enum
@@ -55,6 +48,7 @@ static double pows10[] =
 	1e150, 1e151, 1e152, 1e153, 1e154, 1e155, 1e156, 1e157, 1e158, 1e159, 
 };
 
+#undef pow10
 #define  pow10(x)  fmtpow10(x)
 
 static double