In the file /usr/include/Ecore_X.h there is a struct called _Ecore_X_Event_Window_Prop_Pid_Change at line 414. One element is of type pid_t, which is not declared, since sys/types.h is not included. To fix this, just put #include <sys/types.h> at the top of the file.
no package should ever include Ecore header files without including Ecore.h first