Merge pull request #215 from open-telemetry/main

[TEST] load the .dylib files on macos in the singleton test (open-telemetry#3316)

Author: malkia

api/test/singleton/singleton_test.cc

@@ -55,6 +55,8 @@ void do_something()
 
 #  ifdef _WIN32
   HMODULE component_g = LoadLibraryA("component_g.dll");
+#  elif defined(__APPLE__)
+  void *component_g = dlopen("libcomponent_g.dylib", RTLD_NOW);
 #  else
   void *component_g = dlopen("libcomponent_g.so", RTLD_NOW);
 #  endif
@@ -81,6 +83,8 @@ void do_something()
 
 #  ifdef _WIN32
   HMODULE component_h = LoadLibraryA("component_h.dll");
+#  elif defined(__APPLE__)
+  void *component_h = dlopen("libcomponent_h.dylib", RTLD_NOW);
 #  else
   void *component_h = dlopen("libcomponent_h.so", RTLD_NOW);
 #  endif