Trying to build the latest release tag 96.1.349.

Meson seems to run ok and requirements should be fulfilled:

mzinser@discovery:~/Downloads/The-Powder-Toy-96.1.349> meson build-debug
The Meson build system
Version: 0.56.0
Source dir: /home/mzinser/Downloads/The-Powder-Toy-96.1.349
Build dir: /home/mzinser/Downloads/The-Powder-Toy-96.1.349/build-debug
Build type: native build
Project name: the-powder-toy
Project version: the.cake.is.a.lie
C compiler for the host machine: cc (gcc 7.5.0 "cc (SUSE Linux) 7.5.0")
C linker for the host machine: cc ld.bfd 2.35.1.20201123-7
C++ compiler for the host machine: c++ (gcc 7.5.0 "c++ (SUSE Linux) 7.5.0")
C++ linker for the host machine: c++ ld.bfd 2.35.1.20201123-7
Host machine cpu family: x86_64
Host machine cpu: x86_64
Program python3 found: YES (/usr/bin/python3)
Found pkg-config: /usr/bin/pkg-config (0.29.2)
Run-time dependency luajit found: YES 2.2.0
Run-time dependency libcurl found: YES 7.66.0
Run-time dependency fftw3f found: YES 3.3.9
Run-time dependency threads found: YES
Run-time dependency zlib found: YES 1.2.11
Run-time dependency sdl2 found: YES 2.0.14
Configuring Config.h using configuration
Configuring ElementNumbers.h using configuration
Configuring ToolNumbers.h using configuration
Build targets in project: 1

Found ninja-1.10.2 at /usr/bin/ninja

But actual build fails:

mzinser@discovery:~/Downloads/The-Powder-Toy-96.1.349> cd build-debug/
mzinser@discovery:~/Downloads/The-Powder-Toy-96.1.349/build-debug> ninja
[3/356] Compiling C object powder.p/src_lua_LuaCompat.c.o
FAILED: powder.p/src_lua_LuaCompat.c.o
cc -Ipowder.p -I. -I.. -Isrc -I../src -Idata -I../data -Iresources -I../resources -Isrc/config/powder -I../src/config/powder -I/usr/include/SDL2 -I/usr/include/moonjit-2.2 -fdiagnostics-color=always -pipe -D_FILE_OFFSET_BITS=64 -Wall -Winvalid-pch -g -D_REENTRANT -pthread -U__STRICT_ANSI__ -Wno-unused-result -msse2 -msse -MD -MQ powder.p/src_lua_LuaCompat.c.o -MF powder.p/src_lua_LuaCompat.c.o.d -o powder.p/src_lua_LuaCompat.c.o -c ../src/lua/LuaCompat.c
In file included from ../src/lua/LuaCompat.h:10:0,
                 from ../src/lua/LuaCompat.c:1:
/usr/include/moonjit-2.2/lua.h:38:26: error: expected declaration specifiers or ‘...’ before ‘(’ token
 #define LUA_GLOBALSINDEX (-10002)
                          ^
/usr/include/moonjit-2.2/lua.h:288:49: note: in expansion of macro ‘LUA_GLOBALSINDEX’
 #define lua_pushglobaltable(L) lua_pushvalue(L, LUA_GLOBALSINDEX)
                                                 ^~~~~~~~~~~~~~~~
../src/lua/LuaCompat.c:23:6: note: in expansion of macro ‘lua_pushglobaltable’
 void lua_pushglobaltable(lua_State *L)
      ^~~~~~~~~~~~~~~~~~~
[8/356] Precompiling header ../pch/pch_cpp.h
ninja: build stopped: subcommand failed.

Note: moonjit is the package providing luajit on openSUSE.

Any hints what to check/how to fix this?

That did do the trick, powder is building correctly now. I'll check if I can see something in the moonjit up-stream or file a report with the openSUSE project.

P.S. I did look into the up-stream. Both luajit (since 2017) and moonjit (since 2020) seem to be abandoned, which gives pretty slim chances to get a fix in there.

Could the #ifndef added to powder, so others don't fall into the same trap as me?

Thanks a lot!

P.P.S. I did a build of the head/master branch (2.3.0-dev) of moonjit, which is ahead of the version 2.2.0 distributed by openSUSE. Behaviour unfortunately is the same as reported.