diff --git a/libraries/lib-network-manager/HeadersList.cpp b/libraries/lib-network-manager/HeadersList.cpp
index ca217367d..4203adc3e 100644
--- a/libraries/lib-network-manager/HeadersList.cpp
+++ b/libraries/lib-network-manager/HeadersList.cpp
@@ -25,6 +25,7 @@
 #include "HeadersList.h"
 
 #include <algorithm>
+#include <cctype>
 
 namespace audacity
 {
diff --git a/libraries/lib-network-manager/curl/CurlResponse.cpp b/libraries/lib-network-manager/curl/CurlResponse.cpp
index 3f4fad280..cab1cdba9 100644
--- a/libraries/lib-network-manager/curl/CurlResponse.cpp
+++ b/libraries/lib-network-manager/curl/CurlResponse.cpp
@@ -12,6 +12,7 @@
 
 #include <cassert>
 #include <map>
+#include <algorithm>
 
 namespace audacity
 {