Fix install with read-only /usr
Installing GVls inside of Flatpak, as we are doing with Builder now, fails because /usr is read-only and GVls installs the vapi/deps there instead of using the install prefix.
Installing src/libgvls-0.14.so.1 to /app/lib
Installing src/gvls.h to /app/include/gvls-0.14
Installing src/gvls-0.14.vapi to /usr/share/vala/vapi
Traceback (most recent call last):
File "/usr/lib/python3.7/site-packages/mesonbuild/mesonmain.py", line 127, in run
return options.run_func(options)
File "/usr/lib/python3.7/site-packages/mesonbuild/minstall.py", line 514, in run
installer.do_install(datafilename)
File "/usr/lib/python3.7/site-packages/mesonbuild/minstall.py", line 343, in do_install
self.install_targets(d)
File "/usr/lib/python3.7/site-packages/mesonbuild/minstall.py", line 450, in install_targets
self.do_copyfile(fname, outname)
File "/usr/lib/python3.7/site-packages/mesonbuild/minstall.py", line 257, in do_copyfile
shutil.copyfile(from_file, to_file)
File "/usr/lib/python3.7/shutil.py", line 121, in copyfile
with open(dst, 'wb') as fdst:
OSError: [Errno 30] Read-only file system: '/usr/share/vala/vapi/gvls-0.14.vapi'
FAILED: meson-install
/usr/bin/meson install --no-rebuild
ninja: build stopped: subcommand failed.
Error: module gvls: Child process exited with code 1