Include what you use with signbit.

Include cmath in a few source files which use signbit and a relying on
magic to happen to use it.

Also Fix nuttiness in SampleClip. No need to #define single character
identifiers.

Change-Id: Iae3352d0cab9aaa6c37d6424f064b3d86fa2e011
Reviewed-on: https://skia-review.googlesource.com/4626
Reviewed-by: Herb Derby <herb@google.com>
Commit-Queue: Ben Wagner <bungeman@google.com>
Commit-Queue: Herb Derby <herb@google.com>

1 files changed, 3 insertions, 1 deletions

diff --git a/tests/Float16Test.cpp b/tests/Float16Test.cpp
index 99835686fa..64873c3fc8 100644
--- a/tests/Float16Test.cpp
+++ b/tests/Float16Test.cpp
@@ -14,6 +14,8 @@
 #include "SkPM4f.h"
 #include "SkRandom.h"
 
+#include <cmath>
+
 static bool eq_within_half_float(float a, float b) {
     const float kTolerance = 1.0f / (1 << (8 + 10));
 
@@ -100,7 +102,7 @@ DEF_TEST(SkFloatToHalf_finite_ftz, r) {
         uint16_t alternate = expected;
         if (is_denorm(expected)) {
             // _finite_ftz() may flush denorms to zero, and happens to keep the sign bit.
-            alternate = signbit(f) ? 0x8000 : 0x0000;
+            alternate = std::signbit(f) ? 0x8000 : 0x0000;
         }
 
         uint16_t actual = SkFloatToHalf_finite_ftz(Sk4f{f})[0];