Fix duplicated methods for POSIX platforms.

src/platform-cygwin.cc

Index: src/platform-cygwin.cc
diff --git a/src/platform-cygwin.cc b/src/platform-cygwin.cc
index 51321c7b33ad0a32bbb08fb304928c27ef9fe402..a9192775b76e9bdc69703e91cf898a3087dec549 100644
--- a/src/platform-cygwin.cc
+++ b/src/platform-cygwin.cc
@@ -63,11 +63,6 @@ double ceiling(double x) {
 static Mutex* limit_mutex = NULL;
 
 
-void OS::PostSetUp() {
-  POSIXPostSetUp();
-}
-
-
 uint64_t OS::CpuFeaturesImpliedByPlatform() {
   return 0;  // Nothing special about Cygwin.
 }
@@ -126,11 +121,6 @@ bool OS::IsOutsideAllocatedSpace(void* address) {
 }
 
 
-size_t OS::AllocateAlignment() {
-  return sysconf(_SC_PAGESIZE);
-}
-
-
 void* OS::Allocate(const size_t requested,
                    size_t* allocated,
                    bool is_executable) {
@@ -147,48 +137,6 @@ void* OS::Allocate(const size_t requested,
 }
 
 
-void OS::Free(void* address, const size_t size) {
-  // TODO(1240712): munmap has a return value which is ignored here.
-  int result = munmap(address, size);
-  USE(result);
-  ASSERT(result == 0);
-}
-
-
-void OS::ProtectCode(void* address, const size_t size) {
-  DWORD old_protect;
-  VirtualProtect(address, size, PAGE_EXECUTE_READ, &old_protect);
-}
-
-
-void OS::Guard(void* address, const size_t size) {
-  DWORD oldprotect;
-  VirtualProtect(address, size, PAGE_READONLY | PAGE_GUARD, &oldprotect);
-}
-
-
-void OS::Sleep(int milliseconds) {
-  unsigned int ms = static_cast<unsigned int>(milliseconds);
-  usleep(1000 * ms);
-}
-
-
-int OS::NumberOfCores() {
-  return sysconf(_SC_NPROCESSORS_ONLN);
-}
-
-
-void OS::Abort() {
-  // Redirect to std abort to signal abnormal program termination.
-  abort();
-}
-
-
-void OS::DebugBreak() {
-  asm("int $3");
-}
-
-
 void OS::DumpBacktrace() {
   // Currently unsupported.
 }