Pass -rdynamic to renderdoccmd link

This ensures replay marker sym is exported, and matches qrenderdoc.

Author: corngood

renderdoccmd/CMakeLists.txt

@@ -67,7 +67,7 @@ elseif(UNIX)
 
     # Make sure that for the target executable we don't throw away
     # any shared libraries.
-    set(LINKER_FLAGS "-Wl,--no-as-needed")
+    set(LINKER_FLAGS "-Wl,--no-as-needed -rdynamic")
 endif()
 
 if(ANDROID)