Replace local MUSL define with global ANDROID_HOST_MUSL

Bug: 190084016
Test: m USE_HOST_MUSL=true bionic-unit-tests-glibc
Change-Id: I56b23576cb24912112d2ae56d8ecc2e3716982fe
diff --git a/tests/dlfcn_test.cpp b/tests/dlfcn_test.cpp
index 2024b45..a9c2b87 100644
--- a/tests/dlfcn_test.cpp
+++ b/tests/dlfcn_test.cpp
@@ -21,6 +21,7 @@
 #include <stdint.h>
 #include <stdio.h>
 #include <string.h>
+#include <sys/cdefs.h>
 #if __has_include(<sys/auxv.h>)
 #include <sys/auxv.h>
 #endif
@@ -1259,7 +1260,7 @@
 }
 
 TEST(dlfcn, dlvsym_smoke) {
-#if !defined(MUSL)
+#if !defined(ANDROID_HOST_MUSL)
   void* handle = dlopen("libtest_versioned_lib.so", RTLD_NOW);
   ASSERT_TRUE(handle != nullptr) << dlerror();
   typedef int (*fn_t)();