Add a non-TLS slot implementation of locale.cpp.

libandroid_support shouldn't be using Bionic's TLS slot. Add a
thread_local based implementation. We can't use the thread_local
implementation in bionic because the linker needs this and pthread
thread-locals (which is how thread_local is implemented) doesn't work
that early.

Test: make checkbuild
Test: adb shell /data/nativetest/bionic-unit-tests/bionic-unit-tests
Bug: android/ndk#300
Change-Id: I7dcbf554ade2264d541d722fa3f86df04926e67a

libc/bionic/locale.cpp

@@ -37,7 +37,15 @@
 
 #include "private/bionic_macros.h"
 
+#if defined(__BIONIC_BUILD_FOR_ANDROID_SUPPORT)
+#define USE_TLS_SLOT 0
+#else
+#define USE_TLS_SLOT 1
+#endif
+
+#if USE_TLS_SLOT
 #include "bionic/pthread_internal.h"
+#endif
 
 // We only support two locales, the "C" locale (also known as "POSIX"),
 // and the "C.UTF-8" locale (also known as "en_US.UTF-8").
@@ -70,6 +78,10 @@ size_t __ctype_get_mb_cur_max() {
   }
 }
 
+#if !USE_TLS_SLOT
+static thread_local locale_t g_current_locale;
+#endif
+
 static pthread_once_t g_locale_once = PTHREAD_ONCE_INIT;
 static lconv g_locale;
 
@@ -163,17 +175,24 @@ char* setlocale(int category, const char* locale_name) {
   return const_cast<char*>(__bionic_current_locale_is_utf8 ? "C.UTF-8" : "C");
 }
 
+static locale_t* get_current_locale_ptr() {
+#if USE_TLS_SLOT
+  return &__get_bionic_tls().locale;
+#else
+  return &g_current_locale;
+#endif
+}
+
 locale_t uselocale(locale_t new_locale) {
-  locale_t* locale_storage = &__get_bionic_tls().locale;
-  locale_t old_locale = *locale_storage;
+  locale_t old_locale = *get_current_locale_ptr();
 
   // If this is the first call to uselocale(3) on this thread, we return LC_GLOBAL_LOCALE.
   if (old_locale == NULL) {
     old_locale = LC_GLOBAL_LOCALE;
   }
 
   if (new_locale != NULL) {
-    *locale_storage = new_locale;
+    *get_current_locale_ptr() = new_locale;
   }
 
   return old_locale;