$ ~/lyx/lyx/configure --enable-qt5
...
Configuration
Host type: x86_64-unknown-linux-gnu
Special build flags: build=development warnings assertions stdlib-debug
C++ Compiler: g++ (8)
C++ Compiler flags: -Wall -Wextra -Wfloat-conversion -fPIC -g -O
C++ Compiler user flags:
Linker flags:
Linker user flags:
Qt Frontend:
Qt version: 5.10.1
Packaging: posix
LyX binary dir: /usr/local/bin
LyX files dir: /usr/local/share/lyx
=== The following minor problems have been detected by configure.
=== Please check the messages below before running 'make'.
=== (see the section 'Problems' in the INSTALL file)
== The found moc compiler is for Qt moc-qt5 5.10.1 but the Qt library version
is 5.10.1.
Configuration of LyX was successful.
Type 'make' to compile the program,
Surely enough after this message make failed. :-)
There were two causes, i) I had to run autogen.sh as the previous run was
probably too old and
ii) I had to install qt5-qtsvg-devel and qt5-qtx11extras-devel.
After that I am on track again. :-)
--
José Abílio
