Fix broken compilation_database support and working directories

[guyben13]

This pull request has 3 parts:

• fix the working directory reset for windows using global working directories

  • We often switch to the file's local directory after which we want to return to the old working directory
  • currently, we instead set the global working directory to the user's home

• make sure that the .clang file we find is converted to absolute path

  • we use findfile to find the .clang.
  • findfile returns an absolute path UNLESS the file is in the current directory
  • as a result, if the .clang file is in the same directory as our code file, but a different one than the current working directory, we end up failing to find the .clang file after returning to the old working directory
  • to fix this, we simply always convert the .clang file to an absolute path

• fix compilation database support

  • there is a bug in the .py file going back 2 years where we use the wrong argument name (meaning compilation database support didn't work for at least 2 years!)
  • in addition, there is a bug where we append the "compile_commands.json" filename to the compilation database filename, resulting in double the filename.

I'm currently using this fix and it works! :D

[smekkley]

It doesn't seem to work. I've added the following in the python script.

with open("/var/tmp/test.txt", "a") as f:
    f.write("test") 

but nothing happens. It is not even executed in my case. The only thing I did was let g:clang_compilation_database = './build' I have json file in build dir.