add header

csrc/cpu/ego_sample_cpu.cpp

 #include "ego_sample_cpu.h"
 
 #include <ATen/Parallel.h>
+#include <process.h>
 
 #include "utils.h"
 

csrc/cpu/hgt_sample_cpu.cpp

 #include "hgt_sample_cpu.h"
 
+#include <process.h>
+
 #include "utils.h"
 
 #define MAX_NEIGHBORS 50

csrc/cpu/neighbor_sample_cpu.cpp

 #include "neighbor_sample_cpu.h"
 
+#include <process.h>
+
 #include "utils.h"
 
 using namespace std;

csrc/cpu/sample_cpu.cpp

 #include "sample_cpu.h"
 
+#include <process.h>
+
 #include "utils.h"
 
 // Returns `rowptr`, `col`, `n_id`, `e_id`