In MSVC static build, if we build Qt with 3rdparty library (e.g. zstd),
cmake will add"zstd" (without "-l" prefix) to Qt6Core.prl. Then we
use this Qt to build a qmake project, compilation will fail due to
missing zstd.obj. Without "-l" prefix, qmake will treat "zstd" as an
object file instead of a library.
Library names in qt_module.pri and qt_lib_*_private.pri are also
missing "-l" prefix.
This is because on most compilers, CMAKE_LINK_LIBRARY_FLAG equals
"-l". But on MSVC, it is an empty string. So we should pass
"-DLINK_LIBRARY_FLAG=-l" for MSVC.
Also add "-L/path/to/library" if the library path is not in default
linker search directories. This will write un-relocatable paths to prl
files only when using 3rdparty libraries to build Qt statically. Usually
it's not a problem.
In addition, CMAKE_CXX_IMPLICIT_INCLUDE_DIRECTORIES is also empty on
MSVC. So The third argument of "$<FILTER>" is empty, it is an invalid
generator expression. This means no include dir will be written to
qt_module.pri and qt_lib_*_private.pri on MSVC. So only use "$<FILTER>"
when CMAKE_CXX_IMPLICIT_INCLUDE_DIRECTORIES is not empty.
Pick-to: 6.1
Change-Id: Ib66f95dc09cf920363a4b9338fb97747dd2f8ab7
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>
Reviewed-by: Alexandru Croitor <alexandru.croitor@qt.io>
2c49f85380