test for c++17 w/ c++14 stdlib

Apparently some of our stdlibs are not even quite c++11 compliant.

Bug: skia:9700
Change-Id: I842c2dd2eba55d576aa60b2b3a4734dbace00f6b
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/259074
Reviewed-by: Mike Klein <mtklein@google.com>
Commit-Queue: Mike Klein <mtklein@google.com>
diff --git a/src/core/SkCanvas.cpp b/src/core/SkCanvas.cpp
index 9dd0f16..26a30d1 100644
--- a/src/core/SkCanvas.cpp
+++ b/src/core/SkCanvas.cpp
@@ -54,8 +54,9 @@
 #define RETURN_ON_NULL(ptr)     do { if (nullptr == (ptr)) return; } while (0)
 #define RETURN_ON_FALSE(pred)   do { if (!(pred)) return; } while (0)
 
-// This is a test: static_assert with no message is a c++17 feature.
-static_assert(true);
+// This is a test: static_assert with no message is a c++17 feature,
+// and std::max() is constexpr only since the c++14 stdlib.
+static_assert(std::max(3,4) == 4);
 
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