--- qt-everywhere-src-6.9.3.old/qtwebengine/src/3rdparty/chromium/third_party/pdfium/core/fpdfapi/page/cpdf_psengine.cpp
+++ qt-everywhere-src-6.9.3/qtwebengine/src/3rdparty/chromium/third_party/pdfium/core/fpdfapi/page/cpdf_psengine.cpp
@@ -18,6 +18,8 @@
 #include "core/fxcrt/fx_safe_types.h"
 #include "core/fxcrt/fx_string.h"
 
+using namespace std;
+
 namespace {
 
 struct PDF_PSOpName {
--- qt-everywhere-src-6.9.3.old/qtwebengine/src/3rdparty/chromium/third_party/pdfium/fxjs/cjs_publicmethods.cpp
+++ qt-everywhere-src-6.9.3/qtwebengine/src/3rdparty/chromium/third_party/pdfium/fxjs/cjs_publicmethods.cpp
@@ -43,6 +43,8 @@
 #include "fxjs/js_resources.h"
 #include "v8/include/v8-container.h"
 
+using namespace std;
+
 // static
 const JSMethodSpec CJS_PublicMethods::GlobalFunctionSpecs[] = {
     {"AFDate_Format", AFDate_Format_static},
--- qt-everywhere-src-6.9.3.old/qtwebengine/src/3rdparty/chromium/third_party/pdfium/fxjs/fx_date_helpers.cpp
+++ qt-everywhere-src-6.9.3/qtwebengine/src/3rdparty/chromium/third_party/pdfium/fxjs/fx_date_helpers.cpp
@@ -18,6 +18,8 @@
 #include "core/fxcrt/fx_system.h"
 #include "fpdfsdk/cpdfsdk_helpers.h"
 
+using namespace std;
+
 namespace fxjs {
 namespace {
 
--- qt-everywhere-src-6.9.3.old/qtwebengine/src/3rdparty/chromium/third_party/pdfium/fxjs/xfa/cfxjse_formcalc_context.cpp
+++ qt-everywhere-src-6.9.3/qtwebengine/src/3rdparty/chromium/third_party/pdfium/fxjs/xfa/cfxjse_formcalc_context.cpp
@@ -57,6 +57,8 @@
 using pdfium::fxjse::kClassTag;
 using pdfium::fxjse::kFuncTag;
 
+using namespace std;
+
 namespace {
 
 // Maximum number of characters Acrobat can fit in a text box.
--- qt-everywhere-src-6.9.3.old/qtwebengine/src/3rdparty/chromium/third_party/pdfium/xfa/fgas/graphics/cfgas_gegraphics.cpp
+++ qt-everywhere-src-6.9.3/qtwebengine/src/3rdparty/chromium/third_party/pdfium/xfa/fgas/graphics/cfgas_gegraphics.cpp
@@ -26,6 +26,8 @@
 #include "xfa/fgas/graphics/cfgas_gepattern.h"
 #include "xfa/fgas/graphics/cfgas_geshading.h"
 
+using namespace std;
+
 namespace {
 
 struct FX_HATCHDATA {