libc++: Update header files list for modules build

This also sets locale when sorting the libc++ files.

Bug: 40440396
Change-Id: I48458e14c7d129261c22231b7d9424555830158d
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/6458361
Commit-Queue: Takuto Ikuta <[email protected]>
Commit-Queue: Junji Watanabe <[email protected]>
Auto-Submit: Takuto Ikuta <[email protected]>
Reviewed-by: Junji Watanabe <[email protected]>
Cr-Commit-Position: refs/heads/main@{#1447569}
NOKEYCHECK=True
GitOrigin-RevId: 3cb62bf4edfafcc99e5408e53f2612763264d6fb

Author: Takuto Ikuta

third_party/libc++/libcxx_headers.gni

@@ -4,7 +4,7 @@
 
 # Generate the list via
 # $ find third_party/libc++/src/include/ -type f | fgrep -v "cxx03" | \
-#   sed -E 's:(.*):"//\1",:g' | sort
+#   sed -E 's:(.*):"//\1",:g' | LANG=C sort
 #
 libcxx_headers = [
   # keep-sorted start
@@ -556,6 +556,7 @@ libcxx_headers = [
   "//third_party/libc++/src/include/__math/traits.h",
   "//third_party/libc++/src/include/__math/trigonometric_functions.h",
   "//third_party/libc++/src/include/__mbstate_t.h",
+  "//third_party/libc++/src/include/__mdspan/aligned_accessor.h",
   "//third_party/libc++/src/include/__mdspan/default_accessor.h",
   "//third_party/libc++/src/include/__mdspan/extents.h",
   "//third_party/libc++/src/include/__mdspan/layout_left.h",
@@ -580,6 +581,7 @@ libcxx_headers = [
   "//third_party/libc++/src/include/__memory/destroy.h",
   "//third_party/libc++/src/include/__memory/destruct_n.h",
   "//third_party/libc++/src/include/__memory/inout_ptr.h",
+  "//third_party/libc++/src/include/__memory/is_sufficiently_aligned.h",
   "//third_party/libc++/src/include/__memory/noexcept_move_assign_container.h",
   "//third_party/libc++/src/include/__memory/out_ptr.h",
   "//third_party/libc++/src/include/__memory/pointer_traits.h",