DO NOT MERGE: Backport to fix xlocale.h issue

Backport ICU60 changes to fix xlocale.h issue that prevents execution of
system/timezone/update-tzdata.py on the current Google linux distro.

ICU60 included some changes that enable compilation of digitlst.cpp
on modern C/C++ toolchains. This commit applies the changes to ICU59.

The follow 3 commits are applied here in the following order:

ICU-12822 digitlst.cpp depends on <string> to include <locale.h> on windows. Include it explicitly
X-SVN-Rev: 39486

ICU-13385 autoconf to detect if xlocale.h exists or not.
X-SVN-Rev: 40568

ICU-13385 Fixed a typo.
X-SVN-Rev: 40570

The patches were downloaded from:
https://github.com/unicode-org/icu/commit/173981e6423f42d0be6f4a9caab0d85d2e7d008e.patch
https://github.com/unicode-org/icu/commit/c620f117ca4ad8eb1a3613d115fc3f4d3871ccb6.patch
https://github.com/unicode-org/icu/commit/730670eba542f48fd377cadabd28a3bb52f48567.patch

The patches applied cleanly with:
git am 173981e6423f42d0be6f4a9caab0d85d2e7d008e.patch
git am c620f117ca4ad8eb1a3613d115fc3f4d3871ccb6.patch
git am 730670eba542f48fd377cadabd28a3bb52f48567.patch

Test: system/timezone/update-tzdata.py executes cleanly with this change
Bug: 137354380
Change-Id: Id10f538bbd4906e9d332ea14dc2f5a65220120ba
Merged-In: Id10f538bbd4906e9d332ea14dc2f5a65220120ba
(cherry picked from commit 42101ab4f8e32bc6cd8c91a122c092ab158e652b)
3 files changed