Ubuntu 18.04 (bionic) build doesn't detect LuaJIT 2.1, can't find LuaJit even with all required dev. packages installed

[juozaspo]

Issue type

• Build issue

Minetest version

Commit: 4ccd18d

OS / Hardware

Operating system: Ubuntu Linux 18.04 (bionic) 64 bits
CPU: Intel Pentium(R) Dual-Core CPU E6300 @ 2.80GHz

Summary

Running cmake (3.10.2) on latest git build, LuaJIT 2.1 cannot be found even if it's dev. files are installed.

-- Could NOT find LuaJit (missing: LUA_INCLUDE_DIR) 
-- LuaJIT not found, using bundled Lua.

Installed lua packages:

liblua5.2-0 5.2.4-1.1build1
liblua5.2-dev 5.2.4-1.1build1
liblua5.3-0 5.3.3-1
liblua5.3-dev 5.3.3-1
libluajit-5.1-2 2.1.0~beta3+dfsg-5.1
libluajit-5.1-common 2.1.0~beta3+dfsg-5.1
libluajit-5.1-dev 2.1.0~beta3+dfsg-5.1
lua5.2 5.2.4-1.1build1
lua5.3 5.3.3-1
luajit 2.1.0~beta3+dfsg-5.1

Ubuntu 18.04 libluajit-5.1-dev package contains /usr/include/luajit-2.1 directory, where FindLuaJIT.cmake in cmake/Modules folder expects path containing include/luajit-2.0 referencing older version of LuaJIT (2.0), not available in ubuntu repositories since version 18.04.

juozas@xubuntu:~/minetest_dev/cmake/Modules$ dpkg -L libluajit-5.1-dev 
/.
/usr
/usr/include
/usr/include/luajit-2.1
/usr/include/luajit-2.1/lauxlib.h
/usr/include/luajit-2.1/lua.h
/usr/include/luajit-2.1/lua.hpp
/usr/include/luajit-2.1/luaconf.h
/usr/include/luajit-2.1/luajit.h
/usr/include/luajit-2.1/lualib.h
/usr/lib
/usr/lib/x86_64-linux-gnu
/usr/lib/x86_64-linux-gnu/libluajit-5.1.a
/usr/lib/x86_64-linux-gnu/pkgconfig
/usr/lib/x86_64-linux-gnu/pkgconfig/luajit.pc
/usr/share
/usr/share/doc
/usr/share/doc/libluajit-5.1-dev
/usr/share/doc/libluajit-5.1-dev/copyright
/usr/lib/x86_64-linux-gnu/libluajit-5.1.so
/usr/share/doc/libluajit-5.1-dev/changelog.Debian.gz

# from FindLuaJIT.cmake 
FIND_PATH(LUA_INCLUDE_DIR luajit.h
	HINTS
	$ENV{LUA_DIR}
	PATH_SUFFIXES include/luajit-2.0 include/luajit-5_1-2.0 include
	PATHS
	~/Library/Frameworks
	/Library/Frameworks
	/sw # Fink
	/opt/local # DarwinPorts
	/opt/csw # Blastwave
	/opt
)

Steps to reproduce

1. Install or upgrade ubuntu to version 18.04 (bionic)
2. Install required dependencies including libluajit-5.1-dev, with latest version 2.1.0~beta3+dfsg-5.1
3. Try to run cmake before building minetest, find out Luajit is not detected.

[rubenwardy]

I can confirm this issue, a workaround is to specify the include dir with -DLUA_INCLUDE_DIR=/path/to/lib/