Fixed build breaking due to #77178 and #86131 (#86290)
Fixed a small issue of matching pthread signature, which was causing the
build to break for the compiler-rt project after adding
-Wcast-function-type-mismatch to -Wextra dignostic group
(https://github.com/llvm/llvm-project/pull/77178 &
https://github.com/llvm/llvm-project/pull/86131).
