Add Options for OpenFOAM build about ycm-generator

[rdnetto]

Could you please open a PR for this? PRs make it easier to review code and preserve attribution. If you've never done so before, you can find some instructions here. You should create the PR against the develop branch.

As for the code itself, could you explain why you're passing in all the WM_ environment variables instead of just using -e?

Also, why are you setting WM_COMPILER and WM_CC to gcc instead of clang? And what about WM_CXX?

[handrake0724]

Thanks for the advice.
I just made a PR.

As for your question,

1. OpenFOAM uses wmake (bash script used in OpenFOAM) as a build system. wmake relies on a lot of environment variables starting with WM_ as below:

WM_LINK_LANGUAGE=c++
WM_ARCH=linux64
WM_OSTYPE=POSIX
WM_THIRD_PARTY_DIR=/opt/OpenFOAM/ThirdParty-3.0.1
WM_PROJECT_VERSION=3.0.1
WM_CXXFLAGS=-O3
WM_CFLAGS=-O3
WM_COMPILER_LIB_ARCH=64
WM_PROJECT_INST_DIR=/opt/OpenFOAM
WM_PROJECT_DIR=/opt/OpenFOAM/OpenFOAM-3.0.1
WM_CXX=g++
WM_LABEL_OPTION=Int32
WM_PROJECT=OpenFOAM
WM_LDFLAGS=-O3
WM_COMPILER=Gcc
WM_MPLIB=SYSTEMOPENMPI
WM_CC=gcc
WM_COMPILE_OPTION=Opt
WM_DIR=/opt/OpenFOAM/OpenFOAM-3.0.1/wmake
WM_LABEL_SIZE=32
WM_PROJECT_USER_DIR=/home/user/OpenFOAM/user-3.0.1
WM_OPTIONS=linux64GccDPInt32Opt
WM_PRECISION_OPTION=DP
WM_ARCH_OPTION=64

Also, since version 3.x.x, there were some changes in the environment variables. So, I just wanted to support all the OpenFOAM versions without knowing a specific version.

1. OpenFOAM supports not only gcc but also intel compiler. But, I could not compile clang with intel compiler 2013 (there might be a way, though). After several tries, I just found that temporarily settting those two variables to Gcc and gcc make config_gen.py work successfully regardless compilers.
2. Yes, you are right. setting WM_CXX to g++ may be needed (at that time, I didn't realize it cause I didn't see any problem).

[rdnetto]

Closing, as discussion is moved to PR (#58)