meson: Update luajit wrap for luajit's rolling releases

With LuaJIT/LuaJIT:1067 , pathing genversion.lua would no longer be
necessary.

subprojects/packagefiles/luajit/src/host/genversion.lua

@@ -0,0 +1,45 @@
+----------------------------------------------------------------------------
+-- Lua script to embed the rolling release version in luajit.h.
+----------------------------------------------------------------------------
+-- Copyright (C) 2005-2023 Mike Pall. All rights reserved.
+-- Released under the MIT license. See Copyright Notice in luajit.h
+----------------------------------------------------------------------------
+
+local args = {...}
+local FILE_ROLLING_H = args[1] or "luajit_rolling.h"
+local FILE_RELVER_TXT = args[2] or "luajit_relver.txt"
+local FILE_LUAJIT_H = args[3] or "luajit.h"
+
+local function file_read(file)
+ local fp = assert(io.open(file, "rb"), "run from the wrong directory")
+ local data = assert(fp:read("*a"))
+ fp:close()
+ return data
+end
+
+local function file_write_mod(file, data)
+ local fp = io.open(file, "rb")
+ if fp then
+ local odata = assert(fp:read("*a"))
+ fp:close()
+ if odata == data then return end
+ end
+ fp = assert(io.open(file, "wb"))
+ assert(fp:write(data))
+ assert(fp:close())
+end
+
+local text = file_read(FILE_ROLLING_H)
+local relver = file_read(FILE_RELVER_TXT):match("(%d+)")
+
+if relver then
+ text = text:gsub("ROLLING", relver)
+else
+ io.stderr:write([[
+**** WARNING Cannot determine rolling release version from git log.
+**** WARNING The 'git' command must be available during the build.
+]])
+ file_write_mod(FILE_RELVER_TXT, "ROLLING\n") -- Fallback for install target.
+end
+
+file_write_mod(FILE_LUAJIT_H, text)

subprojects/packagefiles/luajit/src/host/meson.build

@@ -1,7 +1,3 @@
-minilua = executable('minilua', 'minilua.c',
- dependencies: system_deps,
- native: true)
-
 cpu_family = host_machine.cpu_family()
 if cpu_family == 'x86_64'
  dynasm_arch = 'x64'
@@ -54,7 +50,7 @@ buildvm_arch = custom_target('buildvm_arch.h',
  input: dynasm_dasc,
  output: 'buildvm_arch.h')
 
-buildvm = executable('buildvm', buildvm_src, buildvm_arch,
+buildvm = executable('buildvm', buildvm_src, buildvm_arch, luajit_h,
  dependencies: system_deps,
  include_directories: src_inc,
  native: true)

subprojects/packagefiles/luajit/src/luajit_relver.txt.in

@@ -0,0 +1 @@
+@VCS_CT@

subprojects/packagefiles/luajit/src/meson.build

@@ -75,6 +75,23 @@ ljcore_src = files(
 
 src_inc = include_directories('.')
 
+minilua = executable('minilua', 'host/minilua.c',
+ dependencies: system_deps,
+ native: true)
+
+relver = vcs_tag(command: ['git', 'show', '-s', '--format=%ct'],
+ fallback: 'ROLLING',
+ input: 'luajit_relver.txt.in',
+ output: 'luajit_relver.txt',
+ replace_string: '@VCS_CT@')
+
+luajit_rolling_h = files('luajit_rolling.h')
+
+luajit_h = custom_target('luajit_h',
+ command: [minilua, '@INPUT@', '@OUTPUT@'],
+ input: ['host/genversion.lua', 'luajit_rolling.h', relver],
+ output: 'luajit.h')
+
 subdir('host')
 
 hdrgen = [
@@ -84,7 +101,8 @@ hdrgen = [
  'recdef',
 ]
 
-genheaders = []
+genheaders = [luajit_h]
+
 foreach h: hdrgen
  genheaders += custom_target(h,
  command: [buildvm, '-m', h, '-o', '@OUTPUT@', ljlib_src],