[roll] Roll llvm-project/libc 37c8bd3..b81a156 (2 commits)

b81a156 [libc] Implement process_mrelease. (#117503)
fe1a026 [libc] suppress more clang-cl warnings (#117718)

GitOrigin-RevId: 6db9aa0cd0f95724bf45a017abfe0958755e8b7b
Change-Id: I70d6f5b099ad2fbae6293c2eabbaf034649a2c47

Author: global-integration-roller

third_party/flower

@@ -372,7 +372,7 @@
              gitsubmoduleof="fuchsia"
              path="third_party/llvm-libc/src"
              remote="https://llvm.googlesource.com/llvm-project/libc"
-             revision="37c8bd37266d4f29b0c0a52964d886561b35d9be"/>
+             revision="b81a156be1208cc1049a990ef57b8e034397e0f2"/>
     <project name="third_party/lz4"
              gitsubmoduleof="fuchsia"
              path="third_party/lz4"