Revert "[libFuzzer] Port to Windows"

This reverts r340949 due to bot breakage again.

git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk/lib/fuzzer@340954 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/FuzzerTracePC.cpp b/FuzzerTracePC.cpp
index 7513084..1aba816 100644
--- a/FuzzerTracePC.cpp
+++ b/FuzzerTracePC.cpp
@@ -32,7 +32,8 @@
 uintptr_t __sancov_trace_pc_pcs[fuzzer::TracePC::kNumPCs];
 
 // Used by -fsanitize-coverage=stack-depth to track stack depth
-ATTRIBUTES_INTERFACE_TLS_INITIAL_EXEC uintptr_t __sancov_lowest_stack;
+ATTRIBUTE_INTERFACE __attribute__((tls_model("initial-exec")))
+thread_local uintptr_t __sancov_lowest_stack;
 
 namespace fuzzer {