diff -rupN --no-dereference qtbase-everywhere-src-5.15.8/mkspecs/features/default_post.prf qtbase-everywhere-src-5.15.8-new/mkspecs/features/default_post.prf
--- qtbase-everywhere-src-5.15.8/mkspecs/features/default_post.prf	2022-11-11 08:29:17.000000000 +0100
+++ qtbase-everywhere-src-5.15.8-new/mkspecs/features/default_post.prf	2023-01-08 15:56:15.262009250 +0100
@@ -1,5 +1,14 @@
 # This file is loaded by qmake right after loading the actual project file.
 
+win32:contains(CONFIG, static) {
+        # Ensure defines are set correctly for static build
+        DEFINES -= QT_SHARED
+        DEFINES *= QT_STATIC QT_DESIGNER_STATIC DBUS_STATIC_BUILD PCRE_STATIC PCRE2_STATIC
+        contains(QT_CONFIG, angle): DEFINES *= QT_OPENGL_ES_2_ANGLE_STATIC
+        # Ensure we link against all dependencies statically
+        QMAKE_LFLAGS += -static -static-libstdc++ -static-libgcc
+}
+
 contains(TEMPLATE, ".*(lib|app)"):CONFIG += have_target
 
 !have_target:!force_qt: CONFIG -= qt
@@ -130,17 +139,10 @@ c++latest: CONFIG *= c++2a c++1z c++14 c
     !greaterThan(QT_COMPILER_STDCXX_no_L, 199711): CONFIG += c++11
 }
 c++11|c++14|c++1z|c++2a {
-    # Disable special compiler flags for host builds
-    !host_build|!cross_compile {
-        c++2a:       cxxstd = CXX2A
-        else: c++1z: cxxstd = CXX1Z
-        else: c++14: cxxstd = CXX14
-        else:        cxxstd = CXX11
-    } else {
-        # Fall back to c++11, because since 5.7 c++11 is required everywhere,
-        # including host builds
-        cxxstd = CXX11
-    }
+    c++2a:       cxxstd = CXX2A
+    else: c++1z: cxxstd = CXX1Z
+    else: c++14: cxxstd = CXX14
+    else:        cxxstd = CXX11
 
     # Check if we should disable compiler extensions or not
     isEmpty(QMAKE_CXXFLAGS_GNU$$cxxstd) {
diff -rupN --no-dereference qtbase-everywhere-src-5.15.8/mkspecs/features/qt.prf qtbase-everywhere-src-5.15.8-new/mkspecs/features/qt.prf
--- qtbase-everywhere-src-5.15.8/mkspecs/features/qt.prf	2023-01-08 15:56:06.976989969 +0100
+++ qtbase-everywhere-src-5.15.8-new/mkspecs/features/qt.prf	2023-01-08 15:56:15.263009252 +0100
@@ -259,6 +259,21 @@ for(ever) {
             !isEmpty(MODULE_WINRT_CAPABILITIES_DEVICE): \
                 WINRT_MANIFEST.capabilities_device_default += $$MODULE_WINRT_CAPABILITIES_DEVICE
         }
+
+        # Ensure linking against all required static libraries as defined in mingw-w64-g++ mkspec
+        win32:contains(CONFIG, static) {
+            isEqual(MODULE_NAME, QtCore) {
+                LIBS$$var_sfx += $$QMAKE_LIBS_CORE
+            } else:isEqual(MODULE_NAME, QtGui) {
+                LIBS$$var_sfx += $$QMAKE_LIBS_GUI
+            } else:isEqual(MODULE_NAME, QtNetwork) {
+                LIBS$$var_sfx += $$QMAKE_LIBS_NETWORK
+            } else:isEqual(MODULE_NAME, QtDBus) {
+                LIBS$$var_sfx += $$QMAKE_LIBS_DBUS
+            } else:isEqual(MODULE_NAME, QtOpenGL) {
+                LIBS$$var_sfx += $$QMAKE_LIBS_OPENGL
+            }
+        }
     }
     !isEmpty(BAD_QT):error("Unknown module(s) in QT$$var_sfx: $$replace(BAD_QT, _private$, -private)")