[libcxx] Document new symbols __u64toa and __u32toa on Darwin

Summary:
This is the counterpart for https://reviews.llvm.org/D50130 and
https://reviews.llvm.org/D52391 on Darwin.

Reviewers: EricWF

Subscribers: christof, dexonsmith, cfe-commits, libcxx-commits, lichray

Differential Revision: https://reviews.llvm.org/D52396

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@342849 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/abi/CHANGELOG.TXT b/lib/abi/CHANGELOG.TXT
index 8ae38ec..4c9a597 100644
--- a/lib/abi/CHANGELOG.TXT
+++ b/lib/abi/CHANGELOG.TXT
@@ -27,6 +27,9 @@
 
   x86_64-apple-darwin16.0
   -----------------------
+  Symbol added: __ZNSt3__16__itoa8__u64toaEyPc
+  Symbol added: __ZNSt3__16__itoa8__u32toaEjPc
+
 
 * r333467 - Fix embarrasing typo in uncaught_exceptions.
 
diff --git a/lib/abi/x86_64-apple-darwin.v1.abilist b/lib/abi/x86_64-apple-darwin.v1.abilist
index 1be950f..6d01161 100644
--- a/lib/abi/x86_64-apple-darwin.v1.abilist
+++ b/lib/abi/x86_64-apple-darwin.v1.abilist
@@ -1282,6 +1282,8 @@
 {'type': 'OBJECT', 'is_defined': True, 'name': '__ZNSt3__15wcerrE', 'size': 0}
 {'type': 'OBJECT', 'is_defined': True, 'name': '__ZNSt3__15wclogE', 'size': 0}
 {'type': 'OBJECT', 'is_defined': True, 'name': '__ZNSt3__15wcoutE', 'size': 0}
+{'type': 'FUNC', 'is_defined': True, 'name': '__ZNSt3__16__itoa8__u32toaEjPc'}
+{'type': 'FUNC', 'is_defined': True, 'name': '__ZNSt3__16__itoa8__u64toaEyPc'}
 {'type': 'FUNC', 'is_defined': True, 'name': '__ZNSt3__16__sortIRNS_6__lessIaaEEPaEEvT0_S5_T_'}
 {'type': 'FUNC', 'is_defined': True, 'name': '__ZNSt3__16__sortIRNS_6__lessIccEEPcEEvT0_S5_T_'}
 {'type': 'FUNC', 'is_defined': True, 'name': '__ZNSt3__16__sortIRNS_6__lessIddEEPdEEvT0_S5_T_'}