[llvm] Remove conditional checking for macosx 10.5

[ldionne]

Summary

Back-deploying to macOS 10.5 is not supported anymore, so I don't think
anybody's really using that code path. Removing the conditional logic
allows for a small code simplification.

[benlangmuir]

llvm/lib/Support/LockFileManager.cpp

38

gethostuuid is not available on all Apple platforms, so we should still check for macOS specifically. It looks like some other code is using this pattern to check the platform:

#if defined(__APPLE__)
#include <TargetConditionals.h>
#if TARGET_OS_OSX
...

[dexonsmith]

llvm/lib/Support/LockFileManager.cpp

38

Smaller change would be to drop the __MAC_OS_X_VERSION_MIN_REQUIRED > 1050 check (avoids adding an extra include)... but in either case this doesn't buy us much, since we still need some sort of USE_OSX_GETHOSTUUID flag. If the goal is to remove use of libc++'s __MAC_OS_X_VERSION_MIN_REQUIRED, this could switch to the compiler-provided __ENVIRONMENT_MAC_OS_X_VERSION_MIN_REQUIRED__...

[ldionne]

llvm/lib/Support/LockFileManager.cpp

38

Yeah, that's what I did in D110289. I thought I could simplify it further but it looks like there isn't much that can be done, so I'll abandon this.

llvm/lib/Support/LockFileManager.cpp

 
 #ifdef _WIN32
 #include <windows.h>
 #endif
 #if LLVM_ON_UNIX
 #include <unistd.h>
 #endif
 
-#if defined(__APPLE__) && defined(__MAC_OS_X_VERSION_MIN_REQUIRED) && (__MAC_OS_X_VERSION_MIN_REQUIRED > 1050)
-#define USE_OSX_GETHOSTUUID 1
-#else
-#define USE_OSX_GETHOSTUUID 0
-#endif
-
-#if USE_OSX_GETHOSTUUID
+#if defined(__APPLE__)
 #include <uuid/uuid.h>
 #endif
 
 using namespace llvm;
 
 /// Attempt to read the lock file with the given name, if it exists.
 ///
 /// \param LockFileName The name of the lock file to read.
LockFileManager::readLockFile(StringRef LockFileName) {
   // Delete the lock file. It's invalid anyway.
   sys::fs::remove(LockFileName);
   return None;
 }
 
 static std::error_code getHostID(SmallVectorImpl<char> &HostID) {
   HostID.clear();
 
-#if USE_OSX_GETHOSTUUID
+#if defined(__APPLE__)
   // On OS X, use the more stable hardware UUID instead of hostname.
   struct timespec wait = {1, 0}; // 1 second.
   uuid_t uuid;
   if (gethostuuid(uuid, &wait) != 0)
     return std::error_code(errno, std::system_category());
 
   uuid_string_t UUIDStr;
   uuid_unparse(uuid, UUIDStr);