Fix issues by adding support for floating point values in va_list

src/stdio/src/printf.rs

@@ -36,7 +36,7 @@ pub unsafe fn printf<W: fmt::Write>(mut w: W, format: *const c_char, mut ap: VaL
                     found_percent = false;
                 }
                 'f' | 'F' => {
-                    let a: f64 = mem::transmute(ap.get::<u64>());
+                    let a = ap.get::<f64>();
 
                     w.write_fmt(format_args!("{}", a));
 

tests/atof.c

@@ -2,7 +2,7 @@
 #include <stdio.h>
 
 int main(int argc, char* argv[]) {
-    double d = atof("1.0");
+    double d = atof("-3.14");
     printf("%f\n", d);
     return 0;
 }