[scudo][standalone] Support __BIONIC__

Summary:
Some Android builds that we are interested in define `__BIONIC__`
but not `__ANDROID__`, so expand `SCUDO_ANDROID` to encompass those.

Reviewers: cferris, hctim, pcc, eugenis, morehouse

Subscribers: krytarowski, #sanitizers, llvm-commits

Tags: #sanitizers, #llvm

Differential Revision: https://reviews.llvm.org/D71772

Author: Kostya Kortchinsky

compiler-rt/lib/scudo/standalone/platform.h

@@ -9,13 +9,17 @@
 #ifndef SCUDO_PLATFORM_H_
 #define SCUDO_PLATFORM_H_
 
+// Transitive includes of stdint.h specify some of the defines checked below.
+#include <stdint.h>
+
 #if defined(__linux__)
 #define SCUDO_LINUX 1
 #else
 #define SCUDO_LINUX 0
 #endif
 
-#if defined(__ANDROID__)
+// See https://android.googlesource.com/platform/bionic/+/master/docs/defines.md
+#if defined(__BIONIC__)
 #define SCUDO_ANDROID 1
 #else
 #define SCUDO_ANDROID 0