Added test for the dtrace program and enables its use if found
diff --git a/CMakeLists.txt b/CMakeLists.txt
index 7fe4aa3..cd874b2 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -67,7 +67,12 @@
 if(CMAKE_SYSTEM_NAME STREQUAL Android)
   set(ENABLE_DTRACE_DEFAULT OFF)
 else()
-  set(ENABLE_DTRACE_DEFAULT ON)
+  find_program(DTRACEPROG dtrace)
+  if(DTRACEPROG)
+    set(ENABLE_DTRACE_DEFAULT ON)
+  else()
+    set(ENABLE_DTRACE_DEFAULT OFF)
+  endif()
 endif()
 option(ENABLE_DTRACE "enable dtrace support" ${ENABLE_DTRACE_DEFAULT})