[roll] Roll llvm-project/libc c1d000b..4a406d5 (2 commits)

4a406d5 [libc] fix sysconf test for rv32 (#162685)
1311404 [libc][docs] Update VSCode instructions for full host build (#162626)

Rolled-Repo: https://llvm.googlesource.com/llvm-project/libc
Rolled-Commits: c1d000bc46ce10..4a406d5e5e033a
Roller-URL: https://cr-buildbucket.appspot.com/build/8701461112656071825
CQ-Do-Not-Cancel-Tryjobs: true
Cq-Include-Trybots: luci.turquoise.global.try:run-postsubmit-tryjobs
Change-Id: Ifa1a83d9dcc95c1f0417e86d53730b03189e18be
Reviewed-on: https://fuchsia-review.googlesource.com/c/fuchsia/+/1387958
Commit-Queue: GI Roller <global-integration-roller@fuchsia-infra.iam.gserviceaccount.com>
diff --git a/manifests/third_party/all b/manifests/third_party/all
index 984e3a9..6bd87c7 100644
--- a/manifests/third_party/all
+++ b/manifests/third_party/all
@@ -295,7 +295,7 @@
     <project name="llvm-project/libc"
              path="third_party/llvm-libc/src"
              remote="https://llvm.googlesource.com/llvm-project/libc"
-             revision="c1d000bc46ce10865fdb7f3c46288065d06029f3"/>
+             revision="4a406d5e5e033a8ef38ab3424709c8031c20a9ca"/>
     <project name="third_party/luci-go"
              path="third_party/luci-go"
              revision="fd977bf9e01d199a529f28af6dc10fe0fa35d9e7"
diff --git a/third_party/llvm-libc/src b/third_party/llvm-libc/src
index c1d000b..4a406d5 160000
--- a/third_party/llvm-libc/src
+++ b/third_party/llvm-libc/src
@@ -1 +1 @@
-Subproject commit c1d000bc46ce10865fdb7f3c46288065d06029f3
+Subproject commit 4a406d5e5e033a8ef38ab3424709c8031c20a9ca