meson: improve a bit lua detection and output.

In my OS, lua 5.1 binary is called 'lua-5.1' (with hyphen), so I add
this in the list. Also I improve the summary output to display the found
lua binary, which is useful for debugging and for packagers to know
which lua binary is being used (especially now that we install a
lua.interp, even on Linux).

meson.build

@@ -1110,12 +1110,13 @@ endif
 ## Lua
 
 have_lua = false
+have_lua_output = have_lua
 # At time of writing, lua-lgi works with Lua 5.1, 5.2, 5.3 and LuaJIT2, but we
 # support only Lua 5.1 API. See: https://gitlab.gnome.org/GNOME/gimp/-/issues/11876
 if get_option('lua').allowed()
   have_lua_lgi = false
 
-  foreach lua_bin : [ 'luajit', 'lua5.1', 'lua' ]
+  foreach lua_bin : [ 'luajit', 'lua5.1', 'lua-5.1', 'lua' ]
     lua = find_program(lua_bin, required: false)
 
     if lua.found() and meson.can_run_host_binaries()
@@ -1177,6 +1178,8 @@ if get_option('lua').allowed()
     warning(lua_warning)
     warnings += lua_warning
   endif
+
+  have_lua_output = '@0@ (@1@)'.format(have_lua, have_lua_lgi ? lua.full_path() : 'no working lua-lgi found!')
 endif
 
 # Check for XML tools
@@ -2112,7 +2115,7 @@ final_message = [
 '''  PDF (export):        @0@'''.format(cairopdf.found()),
 '''  Print:               @0@'''.format(have_print),
 '''  Javascript plug-ins: @0@'''.format(have_javascript),
-'''  Lua plug-ins:        @0@'''.format(have_lua),
+'''  Lua plug-ins:        @0@'''.format(have_lua_output),
 '''  Vala plug-ins:       @0@'''.format(have_vala),
 '''  TWAIN (Win32):       @0@'''.format(platform_windows),
 '''  WMF:                 @0@'''.format(wmf.found()),