Ignore dependency commands

[chrta]

When creating the json compilation database using "bear make ..." and the makefile generates dependency files, there may be duplicate entries in the variable compileCommands in constructCompileCommands(), one entry for the dependency file generation, one entry for the actual compilation.

This patch filters the commands that contain "-M" or "-MM". The will be ignored.

[lqi]

This is a valid point, separated entries for generating dependencies and compilation cause duplicated violations. However, at the same time, it's very common for Objective-C projects have things like -MMD -MF main.dep -c foo.cpp -o foo.o in the compile_command.json, The second example generates dependencies and compiled object along the way.

I was wondering if this should be a fix on Bear side. Keeping this track requires us taking more scenarios into consideration.

Or another idea might be adding a filter to Results, where it removes duplicated violations existing in different ViolationSets.

Look forward to your opinions.

[chrta]

Ignore Dependency Commands

I don't know if bear should do this. In my opinion dependency file generation is only to aid the build tool (like make) to get the dependencies right. It has no influence on the created AST. So commands that only do dependency file generation (without compilation) need not be part of compile_command.json.

Remove Duplications

As mentioned here: http://clang.llvm.org/docs/JSONCompilationDatabase.html:

There can be multiple command objects for the same file, for example if the same source file is compiled with different configurations.

So we should remove duplicated violations. This would also allow to check various build configurations in one oclint run (e.g. like cppcheck does).

[lqi]

For this case, I agree with removing duplication for reporting purposes. New issue #80 created. Sincerely thank you for this great pull request. It could eventually make two projects better.