[libc++] Remove empty header xlocale/xlocale.h

Summary:
I can't think of a reason for shipping this empty header. If there is
a reason to do so, then hopefully this review can uncover it.

Reviewers: mclow.lists, EricWF

Subscribers: mgorny, christof, jkorous, dexonsmith, libcxx-commits

Differential Revision: https://reviews.llvm.org/D59137

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@355829 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/include/CMakeLists.txt b/include/CMakeLists.txt
index 3bd09b3..9880115 100644
--- a/include/CMakeLists.txt
+++ b/include/CMakeLists.txt
@@ -183,7 +183,6 @@
     support/xlocale/__nop_locale_mgmt.h
     support/xlocale/__posix_l_fallback.h
     support/xlocale/__strtonum_fallback.h
-    support/xlocale/xlocale.h
     )
 endif()
 
diff --git a/include/support/xlocale/xlocale.h b/include/support/xlocale/xlocale.h
deleted file mode 100644
index e69de29..0000000
--- a/include/support/xlocale/xlocale.h
+++ /dev/null