diff --git a/flang-rt/lib/runtime/complex-reduction.h b/flang-rt/lib/runtime/complex-reduction.h
index 44c52fb02fa43..43854462496df 100644
--- a/flang-rt/lib/runtime/complex-reduction.h
+++ b/flang-rt/lib/runtime/complex-reduction.h
@@ -17,6 +17,7 @@
 #include "flang/Common/float128.h"
 #include "flang/Runtime/entry-names.h"
 #include <complex.h>
+#include <stdbool.h>
 
 struct CppDescriptor; /* dummy type name for Fortran::runtime::Descriptor */
 
diff --git a/flang/include/flang/Runtime/freestanding-tools.h b/flang/include/flang/Runtime/freestanding-tools.h
index 6753b7a24ebe1..7ef7cc74f213b 100644
--- a/flang/include/flang/Runtime/freestanding-tools.h
+++ b/flang/include/flang/Runtime/freestanding-tools.h
@@ -13,6 +13,7 @@
 #include "flang/Runtime/c-or-cpp.h"
 #include <algorithm>
 #include <cctype>
+#include <cstdlib>
 #include <cstring>
 
 // The file defines a set of utilities/classes that might be