[PATCH] Allow using system luajit

[J. Neuschäfer]

This patch enables the same logic as for other libraries, to allow
a system installation of luajit to be used instead of the bundled
version.

This does currently *not* result in a successful build (tested with
openresty luajit 2.1  as packaged in Debian and Alpine); some more work
is required for that, such as not relying on lua_rawlen or the internal
lj_arch.h header.

It has a second purpose though: Allowing texlive to be built without
luajit (configure --without-luajit), which is a reasonable stop-gap
solution for architectures to which luajit has not been ported yet.
---

This requires autoconf re-generation.
---
 libs/luajit/ac/luajit.ac     |  9 +++++++++
 libs/luajit/ac/withenable.ac |  2 +-
 m4/kpse-luajit-flags.m4      | 10 +++++++++-
 m4/kpse-pkgs.m4              |  1 +
 4 files changed, 20 insertions(+), 2 deletions(-)
 create mode 100644 libs/luajit/ac/luajit.ac

diff --git a/libs/luajit/ac/luajit.ac b/libs/luajit/ac/luajit.ac
new file mode 100644
index 0000000000..7ffb0d3487
--- /dev/null
+++ b/libs/luajit/ac/luajit.ac
@@ -0,0 +1,9 @@
+## libs/luajit/ac/luajit.ac: configure.ac fragment for the TeX Live subdirectory libs/luajit/
+dnl
+dnl Copyright (C) 2012 Peter Breitenlohner <tex-live at tug.org>
+dnl You may freely use, modify and/or distribute this file.
+dnl
+## basic check of system luajit
+KPSE_TRY_LIB([luajit],
+             [#include <luajit.h>],
+             [const char *v = LUAJIT_VERSION;])
diff --git a/libs/luajit/ac/withenable.ac b/libs/luajit/ac/withenable.ac
index 7f7a246e52..547ebaeb25 100755
--- a/libs/luajit/ac/withenable.ac
+++ b/libs/luajit/ac/withenable.ac
@@ -6,4 +6,4 @@ dnl
 dnl extra_dirs = libs/luajit/native
 dnl
 ## configure options and TL libraries required for luajit
-KPSE_WITH_LIB([luajit], , [tree])
+KPSE_WITH_LIB([luajit])
diff --git a/m4/kpse-luajit-flags.m4 b/m4/kpse-luajit-flags.m4
index 1677a72742..ab443e3d42 100644
--- a/m4/kpse-luajit-flags.m4
+++ b/m4/kpse-luajit-flags.m4
@@ -13,7 +13,7 @@
 # LIBS required for the `-ltexluajit' library in libs/luajit/ of the TL tree.
 AC_DEFUN([KPSE_LUAJIT_FLAGS], [dnl
 echo 'tldbg:[$0] called.' >&AS_MESSAGE_LOG_FD
-_KPSE_LIB_FLAGS([luajit], [texluajit], [lt tree],
+_KPSE_LIB_FLAGS([luajit], [texluajit], [lt],
                 [-IBLD/libs/luajit/include],
                 [BLD/libs/luajit/libtexluajit.la],
                 [],
@@ -61,6 +61,14 @@ esac
 echo 'tldbg:[$0] done.' >&AS_MESSAGE_LOG_FD
 ]) # KPSE_LUAJIT_FLAGS
 
+# KPSE_LUAJIT_OPTIONS([WITH-SYSTEM])
+# ----------------------------------
+AC_DEFUN([KPSE_LUAJIT_OPTIONS], [_KPSE_LIB_OPTIONS([luajit], [$1], [pkg-config])])
+
+# KPSE_LUAJIT_SYSTEM_FLAGS
+# ------------------------
+AC_DEFUN([KPSE_LUAJIT_SYSTEM_FLAGS], [_KPSE_PKG_CONFIG_FLAGS([luajit], [luajit])])
+
 # KPSE_LUAJIT_DEFINES
 # -------------------
 # Set the make variable LUAJIT_DEFINES to the CPPFLAGS required when
diff --git a/m4/kpse-pkgs.m4 b/m4/kpse-pkgs.m4
index cd90410f9d..6203bdb40d 100644
--- a/m4/kpse-pkgs.m4
+++ b/m4/kpse-pkgs.m4
@@ -77,6 +77,7 @@ AC_REQUIRE([KPSE_GRAPHITE2_SYSTEM_FLAGS])[]dnl
 AC_REQUIRE([KPSE_TECKIT_SYSTEM_FLAGS])[]dnl
 AC_REQUIRE([KPSE_ICU_SYSTEM_FLAGS])[]dnl
 AC_REQUIRE([KPSE_HARFBUZZ_SYSTEM_FLAGS])[]dnl
+AC_REQUIRE([KPSE_LUAJIT_SYSTEM_FLAGS])[]dnl
 ]) # KPSE_ALL_SYSTEM_FLAGS
 
 # KPSE_UTILS_PKGS()
-- 
2.48.0.rc1.219.gb6b6757d772