Try cleaning your Homebrew cache for neovim.
rm -rf /Library/Caches/Homebrew/neovim--git
brew reinstall --HEAD neovim rm -rf /Library/Caches/Homebrew/neovim--git
brew reinstall --HEAD neovim ==> make VERBOSE=1
Last 15 lines from /Users/jimwharton/Library/Logs/Homebrew/neovim/02.make:
"__Unwind_GetCFA", referenced from:
_lj_err_unwind_dwarf in libluajit.a(lj_err.o)
"__Unwind_RaiseException", referenced from:
_lj_err_throw in libluajit.a(lj_err.o)
"__Unwind_SetGR", referenced from:
_lj_err_unwind_dwarf in libluajit.a(lj_err.o)
"__Unwind_SetIP", referenced from:
_lj_err_unwind_dwarf in libluajit.a(lj_err.o)
ld: symbol(s) not found for architecture x86_64
clang: error: linker command failed with exit code 1 (use -v to see invocation)
make[4]: *** [luajit] Error 1
make[3]: *** [src/luajit] Error 2
make[2]: *** [build/src/luajit-stamp/luajit-install] Error 2
make[1]: *** [CMakeFiles/luajit.dir/all] Error 2
make: *** [all] Error 2
unset LUA_CPATH LUA_PATH
brew reinstall --HEAD neovim