Subdirs project Android build slow

[MartinD]

Hi,
I use two kits:
Qt 5.11.2 Android for armeabi v7a GCC 4.9, Android NDK r11c, Android compile SDK API 29
Qt 5.7.0 MSVC2013

My OS is Win10, I use Qt Creator 4.7.2.

This subdirs project: https://drive.google.com/file/d/1ASMgH7ksESr4R9CCBQAe2jLGz1BsN_M3/view?usp=sharing

It builds like 2 seconds for MSVC configuration and 30 seconds for Android configuration (APK creation not included).

I have a real project that is much more complicated and I get unacceptable build times for Android, even when there is no change in the project.

How can I optmiize this dummy project to build in acceptable time (max 5 seconds) for Android?