`choosenim devel` failed
not sure if related to https://github.com/dom96/choosenim/issues/67 but could very well be based on error messages I got

on ubuntu (installed via AWS EC2)

after installing choosenim via my workaround here https://github.com/dom96/choosenim/issues/56#issue-312241440 (since https://github.com/dom96/choosenim/issues/67 failed)

```

nim --version
Nim Compiler Version 0.18.0 [Linux: amd64]
Copyright (c) 2006-2018 by Andreas Rumpf

active boot switches: -d:release -d:useLinenoise
ubuntu@ip-172-31-26-230:~$ choosenim devel
Downloading Nim devel from GitHub
[##################################################] 100.0% 0kb/s
 Extracting devel.tar.gz
   Building Nim #devel
   Warning: Building from latest C sources. They may not be compatible with the Nim version you have chosen to install.
Downloading Nim C sources from GitHub
[##################################################] 100.0% 0kb/s
 Extracting master.tar.gz
   Building C sources
   Building koch
   Building Nim
 Exception: choosenim.nim(206)       choosenim
        ... choosenim.nim(187)       performAction
        ... choosenim.nim(85)        choose
        ... choosenim.nim(72)        chooseVersion
        ... choosenim.nim(46)        installVersion
        ... builder.nim(91)          build
        ... builder.nim(45)          buildCompiler
        ... utils.nim(19)            doCmdRaw
        ... Execution failed with exit code 1
        ... Command: ./koch boot -d:release
        ... Output: iteration: 1
        ... compiler/nim0 c -d:release --nimcache:nimcache/r_linux_amd64 compiler/nim.nim
        ... Hint: used config file '/home/ubuntu/.choosenim/toolchains/nim-#devel/config/nim.cfg' [Conf]
        ... Hint: used config file '/home/ubuntu/.choosenim/toolchains/nim-#devel/compiler/nim.cfg' [Conf]
        ... Hint: system [Processing]

...

        ... Hint: scriptconfig [Processing]
        ... Hint: gcc -c  -w -O3 -fno-strict-aliasing  -I'/home/ubuntu/.choosenim/toolchains/nim-#devel/lib' -o '/home/ubuntu/.choosenim/toolchains/nim-#devel/nimcache/r_linux_amd64/compiler_nim.o' '/home/ubuntu/.choo
senim/toolchains/nim-#devel/nimcache/r_linux_amd64/compiler_nim.c' [Exec]
        ... Error: execution of an external program failed: 'gcc -c  -w -O3 -fno-strict-aliasing  -I'/home/ubuntu/.choosenim/toolchains/nim-#devel/lib' -o '/home/ubuntu/.choosenim/toolchains/nim-#devel/nimcache/r_linu
x_amd64/compiler_nim.o' '/home/ubuntu/.choosenim/toolchains/nim-#devel/nimcache/r_linux_amd64/compiler_nim.c''
        ... FAILURE
     Error: choosenim.nim(206)       choosenim
        ... choosenim.nim(187)       performAction
        ... choosenim.nim(85)        choose
        ... choosenim.nim(72)        chooseVersion
        ... choosenim.nim(46)        installVersion
        ... builder.nim(100)         build
        ... Build failed
```

insterestingly, after rerunning it it succeeds:
```
choosenim devel
  Installed component 'nim'
    Prompt: Symlink for 'nimble' detected in '/home/ubuntu/.nimble/bin'. Can I remove it? [y/N]
    Answer: y
    Removed symlink pointing to /home/ubuntu/.nimble/pkgs/nimble-0.8.10/nimble
  Installed component 'nimble'
  Installed component 'nimgrep'
  Installed component 'nimsuggest'
   Switched to Nim #devel
```

**EDIT**
however, that doesn't seem to actually install devel:

```
choosenim 0.18.1
Version 0.18.1 is a development version of Nim ... If you want to install the development version then run `choosenim devel`
# ok fine, but then:

choosenim devel
      Info: Version #devel already selected

choosenim show
   Channel: devel
   Version: #devel
      Path: /home/ubuntu/.choosenim/toolchains/nim-#devel

which -a nim
/home/ubuntu/.nimble/bin//nim
/home/ubuntu/.linuxbrew/bin/nim


which nim
/home/ubuntu/.nimble/bin//nim

nim --version
Nim Compiler Version 0.18.0 [Linux: amd64]
Copyright (c) 2006-2018 by Andreas Rumpf

active boot switches: -d:release -d:useLinenoise

/home/ubuntu/.nimble/bin//nim --version
Nim Compiler Version 0.18.0 [Linux: amd64]
Copyright (c) 2006-2018 by Andreas Rumpf

git hash: 855956bf617f68ac0be3717329e9e1181e5dc0c6
active boot switches: -d:release

`which nim` --version
Nim Compiler Version 0.18.0 [Linux: amd64]
Copyright (c) 2006-2018 by Andreas Rumpf

git hash: 855956bf617f68ac0be3717329e9e1181e5dc0c6
active boot switches: -d:release
```

raises so many questions...

why does `nim --version` and "`which nim` --version" differ ? (`git hash` shown on latter only, and `active boot switches` differ)