Fix clrjit exports on non-Windows platforms.

src/coreclr/tests/src/Interop/UnmanagedCallersOnly/CMakeLists.txt

@@ -4,7 +4,7 @@ set(SOURCES UnmanagedCallersOnlyDll.cpp )
 
 # add the executable
 add_library (UnmanagedCallersOnlyDll SHARED ${SOURCES})
-target_link_libraries(UnmanagedCallersOnlyDll ${LINK_LIBRARIES_ADDITIONAL}) 
+target_link_libraries(UnmanagedCallersOnlyDll ${LINK_LIBRARIES_ADDITIONAL})
 
 # add the install targets
 install (TARGETS UnmanagedCallersOnlyDll DESTINATION bin)

src/coreclr/tests/src/Interop/UnmanagedCallersOnly/UnmanagedCallersOnlyDll.cpp

@@ -36,20 +36,33 @@ namespace
         int Result;
     };
 
-    void ProxyCall(ProxyCallContext* cxt)
+    void* ProxyCall(void* cxtRaw)
     {
+        auto cxt = (ProxyCallContext*)cxtRaw;
         cxt->Result = CallManagedProc(cxt->CallbackProc, cxt->N);
+        return NULL;
     }
 }
 
 extern "C" DLL_EXPORT int STDMETHODCALLTYPE CallManagedProcOnNewThread(CALLBACKPROC pCallbackProc, int n)
 {
     ProxyCallContext cxt{ pCallbackProc, n, 0 };
+
+#ifdef _WIN32
     std::thread newThreadToRuntime{ ProxyCall, &cxt };
 
     // Wait for new thread to complete
     newThreadToRuntime.join();
 
+#else // _WIN32
+    pthread_t newThreadToRuntime;
+    int ret = pthread_create(&newThreadToRuntime, NULL, ProxyCall, &cxt);
+
+    // Wait for new thread to complete
+    pthread_join(newThreadToRuntime, NULL);
+
+#endif // _WIN32
+
     return cxt.Result;
 }