[fuchsia] Disable build warning.

Fuchsia has no mallinfo() or getrusage(). This silences the build
warnings.

Bug: chromium:921807
Change-Id: Ifbb274efdc99ebdf38a6b6b8760ffd42be6fafa4
Reviewed-on: https://swiftshader-review.googlesource.com/c/SwiftShader/+/31708
Reviewed-by: Nicolas Capens <nicolascapens@google.com>
Tested-by: Fabrice de Gans-Riberi <fdegans@chromium.org>
Kokoro-Presubmit: kokoro <noreply+kokoro@google.com>
diff --git a/third_party/llvm-subzero/lib/Support/Unix/Process.inc b/third_party/llvm-subzero/lib/Support/Unix/Process.inc
index 16f8f5a..b239046 100644
--- a/third_party/llvm-subzero/lib/Support/Unix/Process.inc
+++ b/third_party/llvm-subzero/lib/Support/Unix/Process.inc
@@ -65,7 +65,9 @@
   ::getrusage(RUSAGE_SELF, &RU);
   return { toDuration(RU.ru_utime), toDuration(RU.ru_stime) };
 #else
+#if !defined(__Fuchsia__)
 #warning Cannot get usage times on this platform
+#endif
   return { std::chrono::microseconds::zero(), std::chrono::microseconds::zero() };
 #endif
 }
@@ -107,7 +109,9 @@
     return EndOfMemory - StartOfMemory;
   return 0;
 #else
+#if !defined(__Fuchsia__)
 #warning Cannot get malloc info on this platform
+#endif
   return 0;
 #endif
 }