diff -rupN --no-dereference qtbase-everywhere-src-5.15.12/src/src.pro qtbase-everywhere-src-5.15.12-new/src/src.pro
--- qtbase-everywhere-src-5.15.12/src/src.pro	2023-10-17 14:50:53.000000000 +0200
+++ qtbase-everywhere-src-5.15.12-new/src/src.pro	2024-02-15 09:58:45.332371462 +0100
@@ -153,7 +153,7 @@ src_plugins.target = sub-plugins
 src_android.subdir = $$PWD/android
 
 # this order is important
-!qtConfig(system-zlib)|cross_compile {
+!qtConfig(system-zlib) {
     SUBDIRS += src_qtzlib
     !qtConfig(system-zlib) {
         src_3rdparty_libpng.depends += src_corelib
diff -rupN --no-dereference qtbase-everywhere-src-5.15.12/src/tools/bootstrap/bootstrap.pro qtbase-everywhere-src-5.15.12-new/src/tools/bootstrap/bootstrap.pro
--- qtbase-everywhere-src-5.15.12/src/tools/bootstrap/bootstrap.pro	2023-10-17 14:50:53.000000000 +0200
+++ qtbase-everywhere-src-5.15.12-new/src/tools/bootstrap/bootstrap.pro	2024-02-15 09:58:45.335371371 +0100
@@ -158,7 +158,9 @@ macx {
         ../../corelib/io/qstandardpaths_win.cpp
 }
 
-!qtConfig(system-zlib)|cross_compile {
+cross_compile {
+    LIBS += -lz
+} else:!qtConfig(system-zlib) {
     include(../../3rdparty/zlib.pri)
 } else {
     CONFIG += no_core_dep