diff --git a/src/PYTHON/python_impl.cpp b/src/PYTHON/python_impl.cpp
index aaa4f74c69..9c650330af 100644
--- a/src/PYTHON/python_impl.cpp
+++ b/src/PYTHON/python_impl.cpp
@@ -15,6 +15,7 @@
    Contributing author: Richard Berger and Axel Kohlmeyer (Temple U)
 ------------------------------------------------------------------------- */
 
+#include <cstdlib>
 #include <Python.h>
 #include "lmppython.h"
 #include "force.h"
diff --git a/src/USER-MEAMC/meam.h b/src/USER-MEAMC/meam.h
index 42fd722e01..bb40202243 100644
--- a/src/USER-MEAMC/meam.h
+++ b/src/USER-MEAMC/meam.h
@@ -3,7 +3,6 @@
 
 #include "memory.h"
 #include <cmath>
-#include <cstdlib>
 
 #define maxelt 5
 
diff --git a/src/compute_reduce_chunk.cpp b/src/compute_reduce_chunk.cpp
index f31672ef74..5eda71b21b 100644
--- a/src/compute_reduce_chunk.cpp
+++ b/src/compute_reduce_chunk.cpp
@@ -12,7 +12,8 @@
 ------------------------------------------------------------------------- */
 
 #include <mpi.h>
-#include <string.h>
+#include <cstring>
+#include <cstdlib>
 #include "compute_reduce_chunk.h"
 #include "atom.h"
 #include "update.h"
diff --git a/src/fix_vector.cpp b/src/fix_vector.cpp
index 6387af7676..5657e59ab0 100644
--- a/src/fix_vector.cpp
+++ b/src/fix_vector.cpp
@@ -11,6 +11,7 @@
    See the README file in the top-level LAMMPS directory.
 ------------------------------------------------------------------------- */
 
+#include <cstdlib>
 #include <cstring>
 #include "fix_vector.h"
 #include "update.h"
diff --git a/src/lammps.cpp b/src/lammps.cpp
index f8d04c9323..320d89ed52 100644
--- a/src/lammps.cpp
+++ b/src/lammps.cpp
@@ -13,6 +13,7 @@
 
 #include <mpi.h>
 #include <cstring>
+#include <cstdlib>
 #include <cctype>
 #include <map>
 #include <string>
diff --git a/src/variable.cpp b/src/variable.cpp
index ea7f3044d7..1416754073 100644
--- a/src/variable.cpp
+++ b/src/variable.cpp
@@ -26,6 +26,7 @@
 #include "region.h"
 #include "modify.h"
 #include "compute.h"
+#include "input.h"
 #include "fix.h"
 #include "fix_store.h"
 #include "force.h"