[llvm-exegesis] Change preprocessor directives for getCurrentTID

This patch changes the preprocessor directives surrounding
getCurrentTID, particularly moving it out of the block that is only
defined when not building for Android. The getCurrentTID function is
called in places that only require Linux definitions, so this function
should have the same preprocessor scoping around it to prevent link time
failures.

Author: boomanaiden154

llvm/tools/llvm-exegesis/lib/SubprocessMemory.cpp

@@ -22,7 +22,7 @@
 namespace llvm {
 namespace exegesis {
 
-#if defined(__linux__) && !defined(__ANDROID__)
+#if defined(__linux__)
 
 long SubprocessMemory::getCurrentTID() {
   // We're using the raw syscall here rather than the gettid() function provided
@@ -31,6 +31,8 @@ long SubprocessMemory::getCurrentTID() {
   return syscall(SYS_gettid);
 }
 
+#if !defined(__ANDROID__)
+
 Error SubprocessMemory::initializeSubprocessMemory(pid_t ProcessID) {
   // Add the PID to the shared memory name so that if we're running multiple
   // processes at the same time, they won't interfere with each other.
@@ -157,7 +159,8 @@ Expected<int> SubprocessMemory::setupAuxiliaryMemoryInSubprocess(
 
 SubprocessMemory::~SubprocessMemory() {}
 
-#endif // defined(__linux__) && !defined(__ANDROID__)
+#endif // !defined(__ANDROID__)
+#endif // defined(__linux__)
 
 } // namespace exegesis
 } // namespace llvm