MSYS2: the command gtk-3-fortran.exe is not installed in the system

[vmagnin]

Describe the bug
When make -j install DESTDIR=/, the command gtk-3-fortran.exe is not installed in the system:

...
-- Installing: /ucrt64/include/gtk-3-fortran/handlers_gtk_fortran.mod
-- Installing: /ucrt64/include/gtk-3-fortran/pango.mod
-- Installing: /ucrt64/bin/gtk-3-fortran-modscan
-- Installing: /ucrt64/bin/gtk-3-fortran-pymodscan
CMake Error at src/cmake_install.cmake:71 (file):
  file INSTALL cannot find
  "D:................./gtk-fortran/build/src/gtk-3-fortran": File
  exists.
Call Stack (most recent call first):
  cmake_install.cmake:42 (include)
make: *** [Makefile:130: install] Error 1

Expected behavior
Should be installed.

Your system:

• OS version: MSYS2 / Windows10
• GTK branch: gtk3-dev

Additional context
Probably, the .exe extension in Windows is causing the problem.
The command gtk-4-fortran.exe is installed: we should compare with the CMake files in the gtk4 branch...

[vmagnin]

Same as #270 in the gtk4 branch.

Should fix the problem:

install(TARGETS ${gtk_V_fortran}
  DESTINATION ${CMAKE_INSTALL_BINDIR}
  PERMISSIONS OWNER_READ OWNER_WRITE OWNER_EXECUTE GROUP_READ GROUP_EXECUTE WORLD_READ WORLD_EXECUTE
)