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/time_test.cpp b/tests/time_test.cpp
index 85c5390..5fc4cad 100644
--- a/tests/time_test.cpp
+++ b/tests/time_test.cpp
@@ -20,6 +20,7 @@
 #include <gtest/gtest.h>
 #include <pthread.h>
 #include <signal.h>
+#include <sys/cdefs.h>
 #include <sys/syscall.h>
 #include <sys/types.h>
 #include <sys/wait.h>
@@ -282,7 +283,7 @@
 }
 
 TEST(time, strptime_l) {
-#if !defined(MUSL)
+#if !defined(ANDROID_HOST_MUSL)
   setenv("TZ", "UTC", 1);
 
   struct tm t;