Bug 1492121 - Enable Base Profiler by default on Linux and Mac - r=njn

Android not implemented yet.
Windows not working yet when packaged, so disabled by default, but may be
enabled locally by uncommenting `#define MOZ_BASE_PROFILER` where indicated in
BaseProfiler.h.

Differential Revision: https://phabricator.services.mozilla.com/D31927

--HG--
extra : moz-landing-system : lando

mozglue/baseprofiler/public/BaseProfiler.h

@@ -23,9 +23,9 @@
 // #included wherever Base Profiler may be used.
 
 #ifdef MOZ_GECKO_PROFILER
-// Disable Base Profiler for now; will be enabled on supported platforms in
-// later patches.
-#  if 0
+// Enable Base Profiler on Mac and Non-Android Linux, which are supported.
+// (Android not implemented yet. Windows not working yet when packaged.)
+#  if defined(XP_MACOSX) || (defined(XP_LINUX) && !defined(ANDROID))
 #    define MOZ_BASE_PROFILER
 #  else
 // Other platforms are currently not supported. But you may uncomment the