Disable FORTIFY on ASAN builds

FORTIFY's *_chk functions mess with ASAN's library function
interceptors, which can apparently result in false-positives.

Since adding even more complexity to every run-time check condition in
FORTIFY doesn't seem like a great idea, and the majority of our builds
will still use FORTIFY anyway, turning FORTIFY off here seems
reasonable.

Bug: 63104159
Test: checkbuild on internal master + CtsBionicTestCases. No new
failures.

Change-Id: Id32e551e28ee70a9815ad140c3253b86f03de63f
diff --git a/tests/Android.bp b/tests/Android.bp
index 084d393..ea3f39f 100644
--- a/tests/Android.bp
+++ b/tests/Android.bp
@@ -192,6 +192,26 @@
     },
 }
 
+// If building this fails, then we have both FORTIFY and ASAN enabled, which
+// isn't desirable. (Ideally, we'd emit FORTIFY diagnostics even with ASAN
+// enabled, but that's not a reality today.) This is meant to be otherwise
+// unused.
+cc_test_library {
+    name: "fortify_disabled_for_asan",
+    cflags: [
+        "-Werror",
+        "-D_FORTIFY_SOURCE=2",
+        // "sanitize: address" doesn't work on platforms where libasan isn't
+        // enabled. Since the intent is just to build this, we can get away with
+        // passing this flag on its own.
+        "-fsanitize=address",
+    ],
+    // Ignore that we don't have ASAN symbols linked in.
+    allow_undefined_symbols: true,
+    srcs: ["fortify_compilation_test.cpp"],
+    clang: true,
+}
+
 cc_test_library {
     name: "libfortify1-tests-clang",
     defaults: ["bionic_fortify_tests_defaults", "bionic_tests_defaults"],