Migrate libstdc++ to ndk_library.

Test: make checkbuild
Bug: http://b/30465923
Change-Id: I3b75b4e7fa652c83846c5978f9908e8b32d43aa7
diff --git a/libc/Android.bp b/libc/Android.bp
index c9b2f93..c67e23f 100644
--- a/libc/Android.bp
+++ b/libc/Android.bp
@@ -2110,4 +2110,10 @@
     first_version: "9",
 }
 
+ndk_library {
+    name: "libstdc++.ndk",
+    symbol_file: "libstdc++.map.txt",
+    first_version: "9",
+}
+
 subdirs = ["malloc_debug"]
diff --git a/libc/libstdc++.map.txt b/libc/libstdc++.map.txt
index 12e26cd..6b8d092 100644
--- a/libc/libstdc++.map.txt
+++ b/libc/libstdc++.map.txt
@@ -1,18 +1,19 @@
 LIBC_O {
   global:
+    _ZSt7nothrow; # var
+    _ZTV9type_info; # var introduced-arm=9 introduced-mips=9
     _ZdaPv;
     _ZdaPvRKSt9nothrow_t;
     _ZdlPv;
     _ZdlPvRKSt9nothrow_t;
-    _Znam; # arm64 x86_64 mips64
-    _ZnamRKSt9nothrow_t; # arm64 x86_64 mips64
-    _Znwm; # arm64 x86_64 mips64
-    _ZnwmRKSt9nothrow_t; # arm64 x86_64 mips64
     _Znaj; # arm x86 mips
     _ZnajRKSt9nothrow_t; # arm x86 mips
+    _Znam; # arm64 x86_64 mips64
+    _ZnamRKSt9nothrow_t; # arm64 x86_64 mips64
     _Znwj; # arm x86 mips
     _ZnwjRKSt9nothrow_t; # arm x86 mips
-    _ZSt7nothrow;
+    _Znwm; # arm64 x86_64 mips64
+    _ZnwmRKSt9nothrow_t; # arm64 x86_64 mips64
     __cxa_guard_abort;
     __cxa_guard_acquire;
     __cxa_guard_release;