Personally I prefer sfdk over Qt Creator for this kind of stuff (i.e. when I don’t need to actually edit the code):
sfdk check -s harbour RPMS/harbour-simplecrop-1.6.4-1.6.4.armv7hl.rpm
But the result should be the same as what you get when building with Qt Creator.
I get the same linking errors as you do, but on the “Requires” section, I get:
Requires
========
PASSED
@marcelpol is probably on the right track, removing the devel packages from the build target might be the easiest way:
$ sfdk tools exec SailfishOS-3.4.0.24-armvhl
[SailfishOS-3.4.0.24-armv7hl] ~ # rpm -e --nodeps freetype-devel libtiff-devel openjpeg-devel libjpeg-turbo-devel
Please note that this will kind of break your build target, so you might want to install the packages back after building your package:
$ sfdk tools exec SailfishOS-3.4.0.24-armvhl
[SailfishOS-3.4.0.24-armv7hl] ~ # zypper in freetype-devel libtiff-devel openjpeg-devel libjpeg-turbo-devel