[GWP-ASan] Disable GWP-ASan on Android for now.

[hctim]

Summary

Temporarily disable GWP-ASan for android until the bugs at:
http://lab.llvm.org:8011/builders/sanitizer-x86_64-linux-android/builds/87
... can be fixed. See comments for the full bug trace.

[hctim]

Current failures look like this:

FAIL: GWP-ASan-i386 :: double_deletea.cpp (448 of 1106)
******************** TEST 'GWP-ASan-i386 :: double_deletea.cpp' FAILED ********************
Script:
--
: 'RUN: at line 2';     /var/lib/buildbot/sanitizer-buildbot6/sanitizer-x86_64-linux-android/build/llvm/projects/compiler-rt/test/sanitizer_common/android_commands/android_compile.py  /var/lib/buildbot/sanitizer-buildbot6/sanitizer-x86_64-linux-android/build/llvm_build64/bin/clang   -pie -fuse-ld=gold --target=i686-linux-android --sysroot=/var/lib/buildbot/sanitizer-buildbot6/sanitizer-x86_64-linux-android/build/android_ndk/standalone-i686/sysroot -B/var/lib/buildbot/sanitizer-buildbot6/sanitizer-x86_64-linux-android/build/android_ndk/standalone-i686  --driver-mode=g++ -stdlib=libstdc++ -std=c++11 -fsanitize=scudo /var/lib/buildbot/sanitizer-buildbot6/sanitizer-x86_64-linux-android/build/llvm/projects/compiler-rt/test/gwp_asan/double_deletea.cpp -o /var/lib/buildbot/sanitizer-buildbot6/sanitizer-x86_64-linux-android/build/compiler_rt_build_android_i686/test/gwp_asan/I386AndroidConfig/Output/double_deletea.cpp.tmp
: 'RUN: at line 3';   not  /var/lib/buildbot/sanitizer-buildbot6/sanitizer-x86_64-linux-android/build/compiler_rt_build_android_i686/test/gwp_asan/I386AndroidConfig/Output/double_deletea.cpp.tmp 2>&1 | FileCheck /var/lib/buildbot/sanitizer-buildbot6/sanitizer-x86_64-linux-android/build/llvm/projects/compiler-rt/test/gwp_asan/double_deletea.cpp
--
Exit Code: 1

Command Output (stderr):
--
/var/lib/buildbot/sanitizer-buildbot6/sanitizer-x86_64-linux-android/build/llvm/projects/compiler-rt/test/gwp_asan/double_deletea.cpp:5:11: error: CHECK: expected string not found in input
// CHECK: GWP-ASan detected a memory error
          ^
<stdin>:1:1: note: scanning from here
Segmentation fault 
^
<stdin>:2:1: note: possible intended match here
error: Aborted (core dumped)
^

--

[eugenis]

LGTM

compiler-rt/trunk/cmake/config-ix.cmake

if (COMPILER_RT_HAS_SANITIZER_COMMON AND SHADOWCALLSTACK_SUPPORTED_ARCH AND
   set(COMPILER_RT_HAS_SHADOWCALLSTACK TRUE)
 else()
   set(COMPILER_RT_HAS_SHADOWCALLSTACK FALSE)
 endif()
 
 # Note: Fuchsia and Windows are not currently supported by GWP-ASan. Support
 # is planned for these platforms. Darwin is also not supported due to TLS
 # calling malloc on first use.
+# TODO(hctim): Enable this on Android again. Looks like it's causing a SIGSEGV
+# for Scudo and GWP-ASan, further testing needed.
 if (COMPILER_RT_HAS_SANITIZER_COMMON AND GWP_ASAN_SUPPORTED_ARCH AND
-    OS_NAME MATCHES "Android|Linux")
+    OS_NAME MATCHES "Linux")
   set(COMPILER_RT_HAS_GWP_ASAN TRUE)
 else()
   set(COMPILER_RT_HAS_GWP_ASAN FALSE)
 endif()
 pythonize_bool(COMPILER_RT_HAS_GWP_ASAN)

compiler-rt/trunk/lib/gwp_asan/CMakeLists.txt

set(GWP_ASAN_HEADERS
   options.h
   options.inc
   random.h
 )
 
 # Ensure that GWP-ASan meets the delegated requirements of some supporting
 # allocators. Some supporting allocators (e.g. scudo standalone) cannot use any
 # parts of the C++ standard library.
-set(GWP_ASAN_CFLAGS -fno-rtti -fno-exceptions -fPIC -nostdinc++ -pthread)
+set(GWP_ASAN_CFLAGS -fno-rtti -fno-exceptions -nostdinc++ -pthread)
+append_list_if(COMPILER_RT_HAS_FPIC_FLAG -fPIC GWP_ASAN_CFLAGS)
 
 # Remove -stdlib= which is unused when passing -nostdinc++.
 string(REGEX REPLACE "-stdlib=[a-zA-Z+]*" "" CMAKE_CXX_FLAGS ${CMAKE_CXX_FLAGS})
 
 # Options parsing support is optional. GwpAsan is totally independent of
 # sanitizer_common, the options parser is not. This is an optional library
 # that can be used by an allocator to automatically parse GwpAsan options from
 # the environment variable GWP_ASAN_FLAGS, but the allocator can choose to