util: Include bitscan.h directly

Previously bitset.h would include u_math.h to get bitscan.h.  u_math.h
lives in src/gallium/auxiliary/util while both bitset.h and bitscan.h
live in src/util.  Having the one file directly include another file
that lives in the same directory makes much more sense.

As a side-effect, several files need to directly include standard header
files that were previously indirectly included.

v2: Fix build break in src/amd/common/ac_nir_to_llvm.c.

Signed-off-by: Ian Romanick <ian.d.romanick@intel.com>
Reviewed-by: Eduardo Lima Mitev <elima@igalia.com>

src/amd/common/ac_nir_to_llvm.c

@@ -28,6 +28,7 @@
 #include "sid.h"
 #include "nir/nir.h"
 #include "util/bitscan.h"
+#include "util/u_math.h"
 #include "ac_shader_abi.h"
 #include "ac_shader_util.h"
 

src/compiler/nir/nir.c

@@ -28,6 +28,7 @@
 #include "nir.h"
 #include "nir_control_flow_private.h"
 #include "util/half_float.h"
+#include <limits.h>
 #include <assert.h>
 #include <math.h>
 

src/compiler/spirv/vtn_alu.c

@@ -21,6 +21,7 @@
  * IN THE SOFTWARE.
  */
 
+#include <math.h>
 #include "vtn_private.h"
 
 /*

src/compiler/spirv/vtn_glsl450.c

@@ -25,6 +25,7 @@
  *
  */
 
+#include <math.h>
 #include "vtn_private.h"
 #include "GLSL.std.450.h"
 

src/util/bitset.h

@@ -31,7 +31,7 @@
 #ifndef BITSET_H
 #define BITSET_H
 
-#include "util/u_math.h"
+#include "util/bitscan.h"
 
 /****************************************************************************
  * generic bitset implementation