docs: 'how-to-build' add a troubleshooting of luasocket

[fukiki]

Signed-off-by: fukiki one.fhh@163.com

What this PR does / why we need it:

Document how-to-build.md should add a troubleshooting of luasocket

fix #3281
fix #3216

Pre-submission checklist:

• Did you explain what problem does this PR solve? Or what new features have been added?
• Have you added corresponding test cases?
• Have you modified the corresponding document?
• Is this PR backward compatible? If it is not backward compatible, please discuss on the mailing list first

[spacewander]

The English version is different from the Chinese one?

[membphis]

I think the makefile has processed this problem. so we call make deps should be enough for users.

https://github.com/apache/apisix/blob/master/Makefile#L55

[fukiki]

@spacewander It should be unclear for my expression, I will modify it

[fukiki]

@membphis This problem occurs after make deps, I will complete the detail and environments

[membphis]

what is the version of your Lua and Luarocks? @fukiki

[fukiki]

@membphis macosx Lua 5.3.5 Luarocks 3.4.0

[spacewander]

It is recommended to use LuaJIT if Lua 5.1 doesn't work.
Using Lua 5.3 may cause more problems, since we don't test it.

[fukiki]

Using Lua 5.3.5 is just for compile luasocket, not for the apisix

[spacewander]

The binary compiled with Lua 5.3 might not work properly with APISIX which runs under LuaJIT. We don't want to deal with weird problem.

[fukiki]

This should be the setting of OS environment variables. The default Lua version of the operating system may not be 5.1 (maxos: Lua 5.4, fedora32: Lua 5.3).
But In APISIX some modules or dependencies require Lua 5.1, such as luasocket.
Therefore, you need to modify the local environment to install Lua 5.1.
If you want to continue to use Lua 5.3 or 5.4, you must use Lua 5.3 or 5.4 to recompile and install dependencies.
I think it's better to remind users in the document : APISIX is recommended to use LuaJIT or Lua 5.1.

[membphis]

for APISIX, we should use luajit or Lua 5.1 always.

For Luarocks 2.* , it works with Lua 5.1 normally, that is fine.
For Luarocks 3.*, it may work with Lua 5.1, 5.2 or 5.3. so we use luarocks install --lua-dir=$(LUAJIT_DIR) rockspec/apisix-master-0.rockspec --tree=deps --only-deps --local in makefile . It means we will use Luajit.

[Firstsawyou]

ci failed，you need to deal with the spaces at the end of the line.

Scan detected 7 error(s) in 2 file(s):
  [./doc/how-to-build.md]:
     121: line has trailing whitespace.
     122: line has trailing whitespace.
     144: line has trailing whitespace.
  [./doc/zh-cn/how-to-build.md]:
     111: line has trailing whitespace.
     117: line has trailing whitespace.
     118: line has trailing whitespace.
     141: line has trailing whitespace.

[membphis]

I think the makefile has processed this problem. so we call make deps should be enough for users.

https://github.com/apache/apisix/blob/master/Makefile#L55

[fukiki]

ci failed，you need to deal with the spaces at the end of the line.

Scan detected 7 error(s) in 2 file(s):
  [./doc/how-to-build.md]:
     121: line has trailing whitespace.
     122: line has trailing whitespace.
     144: line has trailing whitespace.
  [./doc/zh-cn/how-to-build.md]:
     111: line has trailing whitespace.
     117: line has trailing whitespace.
     118: line has trailing whitespace.
     141: line has trailing whitespace.

@Firstsawyou Thanks for your review, I will modify it.

[membphis]

if the lua version is not 5.1, then the bin/apisix will wrong. we need a way to run the CLI with openresty-luajit always.

[fukiki]

Resolved after discussion: using LuaJIT or Lua 5.1 instead is the best solution.
This pr is not too suitable to solve this problem, then close it.