Introduce hwasan mode for linker

This mode instructs the linker to search for libraries in hwasan
subdirectories of all library search paths. This is set up to contain a
hwasan-enabled copy of libc, which is needed for HWASan programs to
operate. There are two ways this mode can be enabled:

* for native binaries, by using the linker_hwasan64 symlink as its
  interpreter
* for apps: by setting the LD_HWASAN environment variable in wrap.sh

Bug: 276930343
Change-Id: I0f4117a50091616f26947fbe37a28ee573b97ad0
diff --git a/tests/dlfcn_test.cpp b/tests/dlfcn_test.cpp
index 3f70279..0c71b2a 100644
--- a/tests/dlfcn_test.cpp
+++ b/tests/dlfcn_test.cpp
@@ -971,9 +971,15 @@
 }
 
 #define ALTERNATE_PATH_TO_SYSTEM_LIB "/system/lib64/" ABI_STRING "/"
+#if __has_feature(hwaddress_sanitizer)
+#define PATH_TO_LIBC PATH_TO_SYSTEM_LIB "hwasan/libc.so"
+#define PATH_TO_BOOTSTRAP_LIBC PATH_TO_SYSTEM_LIB "bootstrap/hwasan/libc.so"
+#define ALTERNATE_PATH_TO_LIBC ALTERNATE_PATH_TO_SYSTEM_LIB "hwasan/libc.so"
+#else
 #define PATH_TO_LIBC PATH_TO_SYSTEM_LIB "libc.so"
 #define PATH_TO_BOOTSTRAP_LIBC PATH_TO_SYSTEM_LIB "bootstrap/libc.so"
 #define ALTERNATE_PATH_TO_LIBC ALTERNATE_PATH_TO_SYSTEM_LIB "libc.so"
+#endif
 
 TEST(dlfcn, dladdr_libc) {
 #if defined(__GLIBC__)