Dead keys don't work when linking against a static Qt build

When I link against a static Qt build, typing characters using dead keys doesn't work. I'll attach an example with a minimalistic program only displaying a QLineEdit and my used (minimalistic) configure statement for Qt to demonstrate the behavior.

If I link the program against my system-wide Qt installation or a custom build using the mentionned configure statement, but with "-static" replaced with "-shared", the program works as expected. Using a German locale here, e. g. typing "^" and "e" results in a "ê".

When the same program is linked against the static build (compiled in the same environment), dead keys don't work: Accent keys seem to be ignored. Typing "^" does nothing (as expected, as it's a dead key), but typing an "e" afterwards only results in an "e" being displayed, not a "ê".