This commit allows compiling LyX with Qt6 when using autotools.
For a successful compilation the following 2 conditions must be met.
1) The Qt6 qmake has to come first in PATH, so that the command
"qmake -v | grep -o 'Qt version .'" returns "Qt version 6".
2) The --enable-qt6 switch has to be passed to the configure command.
If --enable-qt6 is used but Qt6 is not found, Qt5 is tried as a fallback.
If also Qt5 is not found, configuring for Qt4 is attempted.
If --enable-qt6 is not used, then things go as usual. This means that Qt5
is tried first and then Qt4, unless --disable-qt5 is used, in which case
Qt4 is directly attempted. This means that existing scripts should
continue working unmodified.
LyX should compile with Qt6 on windows and linux, and possibly also on
mac, but I could not test that. However, it is not guaranteed that it
works as it should. In particular I am not sure that I got right the
conversion from QRegExp to QRegularExpression. For sure, the syntax
highlighting seems to not work right. Someone in the know should take
a look at that. I am able to load documents and compile them but some
thourough testing is needed. However, when compiling for Qt5 or Qt4,
I tried to make sure that the functionality is preserved.
In particular, the directory frontends/qt4 is renamed to frontends/qt.
Many configurations file have to be updated. All mentions of qt4 in
the source have been audited, and changed to qt if necessary.
The only part that has not been updated is the CMake build system.
This allows to fix distclean properly, since we know that
subdir-objects is used. When it is the case, it is not a good idea for
a Makefile to use a source file which is under the control of another
one. This could not be made to work work with old automake versions
(<1.14).
Therefore we refer directly to object files in Makefile.am instead of
source files. The actually leads to less compilation in tex2lyx.
Update the code here and there to remove compatibility hacks. Update
documentation.
Re-enable the layout test and fix the Length test, which was ovewriting
memory in test_inPixels() because lyxrc did not had a correct layout.
Now configure searches in this order
1. system-installed library
2. code bundled with LyX
If --with-included-mythes or if no mythes library is installed, then
the script selects the bundled version. There should be no cases
leading to error message.
The configure code suggests that the default for
--with-included-(iconv|zlib|hunspell) is "yes", which is wrong: by
default is indeed to use the system libraries.
Change the MyThes detection to use the system version by default.
Also add to the verison information a line which lists the bundled libraries.
Boost.Signals is deprecated. This fixes bug #9943.
The only thing left to do is to rewrite (or get rid of) the boost -mt test
in config/lyxinclude.m4 not to use signals anymore.
As discussed on the list. If no C++11 compiler is found configuration stops
with an error. There are now unneeded parts of boost, the will be removed in
a second commit.
The Reproducible Builds effort (https://wiki.debian.org/ReproducibleBuilds) in Debian (at least) means that 'ar' is built in deterministic mode as default: all timestamps are set to 0.
This is not compatible with the use of the 'u' flag, and therefore ARFLAGS has to be changed from 'cru' to 'cr'.
This gets rid of the harmless but annoying warning
ar: `u' modifier ignored since `D' is the default (see `U')
Use the standard way to check for the resource compiler, as e.g.
libtool does it: AC_CHECK_TOOL does already provide some cross compiling
magic, and we do also get an error now at configure time if windres is not
found.
