Use the start.lua file in data/core as a template

Instead of having a separate start.lua.in file in the scripts directory
and no start.lua file in data/core we use the file data/core/start.lua
as a template for Meson to generate the final start.lua file for release.

In this way people naturally trying to run lite-xl from the source folder
will have a start.lua file albeit without a resolved version number.

Otherwise, when using run-local script or the meson install command the
meson-generated start.lua file will be used as it should be.

scripts/run-local

@@ -76,10 +76,13 @@ copy_lite_build () {
     cp "$builddir/src/lite-xl" "$bindir"
   fi
   mkdir -p "$datadir/core"
-  cp "$builddir/start.lua" "$datadir/core"
   for module_name in core plugins colors fonts; do
     cp -r "data/$module_name" "$datadir"
   done
+  # The start.lua file is generated by meson in $builddir but
+  # there is already a start.lua file in data/core so the command below
+  # should be executed after we copy the data/core directory.
+  cp "$builddir/start.lua" "$datadir/core"
 }
 
 run_lite () {

scripts/start.lua.in

@@ -1,21 +0,0 @@
--- this file is used by lite-xl to setup the Lua environment when starting
-VERSION = "@PROJECT_VERSION@"
-MOD_VERSION = "1"
-
-SCALE = tonumber(os.getenv("LITE_SCALE")) or SCALE
-PATHSEP = package.config:sub(1, 1)
-
-EXEDIR = EXEFILE:match("^(.+)[/\\][^/\\]+$")
-if MACOS_RESOURCES then
-  DATADIR = MACOS_RESOURCES
-else
-  local prefix = EXEDIR:match("^(.+)[/\\]bin$")
-  DATADIR = prefix and (prefix .. '/share/lite-xl') or (EXEDIR .. '/data')
-end
-USERDIR = (os.getenv("XDG_CONFIG_HOME") and os.getenv("XDG_CONFIG_HOME") .. "/lite-xl")
-  or (HOME and (HOME .. '/.config/lite-xl') or (EXEDIR .. '/user'))
-
-package.path = DATADIR .. '/?.lua;' .. package.path
-package.path = DATADIR .. '/?/init.lua;' .. package.path
-package.path = USERDIR .. '/?.lua;' .. package.path
-package.path = USERDIR .. '/?/init.lua;' .. package.path