Fix lldb build on older OSX versions after svn commit r244716

Older OSX versions don't define NSOperatingSystemVersion, so building
lldb gets: error: unknown type name 'NSOperatingSystemVersion'
This patch fixes the build by having GetOSVersionNumbers return false if
__ENVIRONMENT_MAC_OS_X_VERSION_MIN_REQUIRED__ < 101000, causing lldb to
behave the same as it did before the commit.

Reviewed by: jasonmolenda
Subscribers: lldb-commits
Differential Revision: http://reviews.llvm.org/D12396

llvm-svn: 246138

lldb/tools/debugserver/source/MacOSX/MachProcess.mm

@@ -2027,6 +2027,7 @@ MachProcess::GetOSVersionNumbers (uint64_t *major, uint64_t *minor, uint64_t *pa
 {
     bool success = false;
 
+#if (__ENVIRONMENT_MAC_OS_X_VERSION_MIN_REQUIRED__ >= 101000)
     NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init];
 
     NSOperatingSystemVersion vers = [[NSProcessInfo processInfo] operatingSystemVersion];
@@ -2040,6 +2041,7 @@ MachProcess::GetOSVersionNumbers (uint64_t *major, uint64_t *minor, uint64_t *pa
     success = true;
 
     [pool drain];
+#endif
 
     return success;
 }