Fix warnings on VS2015 x86_64 build

TBR=bungeman@google.com

Review URL: https://codereview.chromium.org/1276133002
diff --git a/gm/lightingshader.cpp b/gm/lightingshader.cpp
index 687968a..771c0bc 100644
--- a/gm/lightingshader.cpp
+++ b/gm/lightingshader.cpp
@@ -38,7 +38,7 @@
                 locY = 0.0f;
                 locZ = 0.0f;
             }
-            locZ = sqrt(1.0f - locZ);
+            locZ = sqrtf(1.0f - locZ);
             unsigned char r = static_cast<unsigned char>((0.5f * locX + 0.5f) * 255);
             unsigned char g = static_cast<unsigned char>((-0.5f * locY + 0.5f) * 255);
             unsigned char b = static_cast<unsigned char>((0.5f * locZ + 0.5f) * 255);
diff --git a/gyp/zlib.gyp b/gyp/zlib.gyp
index 1a79715..93affea 100644
--- a/gyp/zlib.gyp
+++ b/gyp/zlib.gyp
@@ -4,6 +4,9 @@
 # found in the LICENSE file.
 
 {
+  'variables': {
+    'skia_warnings_as_errors': 0,
+  },
   'targets': [
   {
     # Only used by win, down below.
diff --git a/src/gpu/GrDrawTarget.cpp b/src/gpu/GrDrawTarget.cpp
index 2171f1e..9469b3a 100644
--- a/src/gpu/GrDrawTarget.cpp
+++ b/src/gpu/GrDrawTarget.cpp
@@ -256,7 +256,8 @@
     SkASSERT(this->caps()->shaderCaps()->pathRenderingSupport());
     SkASSERT(pathRange);
     SkASSERT(indices);
-    SkASSERT(0 == reinterpret_cast<long>(indices) % GrPathRange::PathIndexSizeInBytes(indexType));
+    SkASSERT(0 == reinterpret_cast<intptr_t>(indices) %
+             GrPathRange::PathIndexSizeInBytes(indexType));
     SkASSERT(transformValues);
 
     // Setup clip
diff --git a/tests/GrMemoryPoolTest.cpp b/tests/GrMemoryPoolTest.cpp
index 81392ce..4f53c1d 100644
--- a/tests/GrMemoryPoolTest.cpp
+++ b/tests/GrMemoryPoolTest.cpp
@@ -106,12 +106,12 @@
         fB = new B();
     }
     virtual void setValues(int v) {
-        fVoidStar = reinterpret_cast<void*>(v);
+        fVoidStar = reinterpret_cast<void*>(static_cast<intptr_t>(v));
         this->INHERITED::setValues(v);
         fB->setValues(v);
     }
     virtual bool checkValues(int v) {
-        return fVoidStar == reinterpret_cast<void*>(v) &&
+        return fVoidStar == reinterpret_cast<void*>(static_cast<intptr_t>(v)) &&
                fB->checkValues(v) &&
                this->INHERITED::checkValues(v);
     }