Fix Android standalone compilation

Fixes standalone Android compilation not working due to `memcpy` not
being flagged as unsafe. This appears to be due to an incompatibility
between how Clang's checker works and how `memcpy` is defined for
Android. This is worked around by omitting the failing test when
compiling for Android.

Bug: 520153663
Change-Id: I783ba9c804f677bad1e9011ad0890dab077bd49a
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/323495
Commit-Queue: Brian Sheedy <bsheedy@google.com>
Auto-Submit: Brian Sheedy <bsheedy@google.com>
Reviewed-by: Kai Ninomiya <kainino@chromium.org>
Commit-Queue: Kai Ninomiya <kainino@chromium.org>

src/utils/warning_nocompile.nc

diff --git a/src/utils/warning_nocompile.nc b/src/utils/warning_nocompile.nc
index 2596a0f..5f7cb45 100644
--- a/src/utils/warning_nocompile.nc
+++ b/src/utils/warning_nocompile.nc
@@ -67,11 +67,18 @@
 }
 
 // -Wunsafe-buffer-usage-in-libc-call: memcpy()
+// This is skipped on Android because with Android Bionic's _FORTIFY_SOURCE,
+// memcpy is a static inline wrapper (__BIONIC_FORTIFY_INLINE). This causes
+// Clang's unsafe-buffer-usage checker to ignore it (as it only matches global
+// functions or std:: functions), which then causes the expected error to not
+// be raised.
+#if !defined(__ANDROID__)
 void TestUnsafeBuffersMemcpy() {
     int x = 1;
     int y = 2;
     memcpy(&y, &x, sizeof(int));  // expected-error {{function 'memcpy' is unsafe}}
 }
+#endif  // !defined(__ANDROID__)
 
 // -Wunsafe-buffer-usage: std::span() constructors
 void TestUnsafeBuffersStdSpanConstructors() {