https://github.com/bitcoin/bitcoin/blob/master/build-aux/m4/bitcoin_qt.m4#L223
AC_MSG_CHECKING(whether to build ]AC_PACKAGE_NAME[ GUI) AC_MSG_CHECKING(whether to build [AC_PACKAGE_NAME] GUI)
https://github.com/bitcoin/bitcoin/blob/master/build-aux/m4/bitcoin_qt.m4#L223
AC_MSG_CHECKING(whether to build ]AC_PACKAGE_NAME[ GUI) AC_MSG_CHECKING(whether to build [AC_PACKAGE_NAME] GUI)
What problem does this cause in practice?
None, just a wrong message. Could also be ignored.
What is wrong with the message?
checking whether to build Bitcoin Core GUI... yes (Qt5)
But well, this is interesting ;-)
Indeed, I've never noticed anything wrong with the message. And I don't know enough about autotools internals to know if this is worrying, or expected behavior.