diff --git a/lib/Support/SystemUtils.cpp b/lib/Support/SystemUtils.cpp
index 98b2fc662cf..034c141f794 100644
--- a/lib/Support/SystemUtils.cpp
+++ b/lib/Support/SystemUtils.cpp
@@ -9,7 +9,8 @@
 #include <algorithm>
 #include <fstream>
 #include <iostream>
-#include <stdlib.h>
+#include <cstdlib>
+#include <alloca.h>
 #include <sys/types.h>
 #include <sys/stat.h>
 #include <fcntl.h>
diff --git a/support/lib/Support/SystemUtils.cpp b/support/lib/Support/SystemUtils.cpp
index 98b2fc662cf..034c141f794 100644
--- a/support/lib/Support/SystemUtils.cpp
+++ b/support/lib/Support/SystemUtils.cpp
@@ -9,7 +9,8 @@
 #include <algorithm>
 #include <fstream>
 #include <iostream>
-#include <stdlib.h>
+#include <cstdlib>
+#include <alloca.h>
 #include <sys/types.h>
 #include <sys/stat.h>
 #include <fcntl.h>
diff --git a/tools/bugpoint/SystemUtils.cpp b/tools/bugpoint/SystemUtils.cpp
index 98b2fc662cf..034c141f794 100644
--- a/tools/bugpoint/SystemUtils.cpp
+++ b/tools/bugpoint/SystemUtils.cpp
@@ -9,7 +9,8 @@
 #include <algorithm>
 #include <fstream>
 #include <iostream>
-#include <stdlib.h>
+#include <cstdlib>
+#include <alloca.h>
 #include <sys/types.h>
 #include <sys/stat.h>
 #include <fcntl.h>