building msgsteiner on Mac OS requires gcc

[koksal]

Hi,

I'd like to give some feedback on installation instructions after having successfully run OmicsIntegrator on OS X El Capitan (10.11).

The issue is that on OS X, gcc is actually an alias for the Mac version of the clang compiler, which doesn't support OpenMP. Meanwhile, msgsteiner requires OpenMP support. I found the solution to be as follows:

1. Install the gcc compiler using homebrew:
   brew install gcc
   When installed, the compiler can be accessed via the gcc-6 command.

2. Build the Boost library using homebrew, specifying gcc-6 as the compiler:
   brew install boost --cc=gcc-6
   Without this extra argument, the library will not be visible to gcc when building msgsteiner.

3. Similarly to the other patches, change the msgsteiner Makefile to use g++-6 instead of g++.

I wanted to contribute this piece of information since I spent a fair bit of time making sure msgsteiner could be built using Boost :)

[AmandaKedaigle]

Thanks Ali, this worked for me as well! We now link to this thread in our readme.

Notes for future users:

• Step 1 may take quite a bit of time
• In step 3, when editing the msgsteiner Makefile, change g++ to g++-6.
• You may also need to add -L and -I flags pointed to your installation of boost. In my case, that meant changing the line starting with LDFLAGS to LDFLAGS=-lboost_program_options -lgomp -I /usr/local/Cellar/boost/1.62.0/include/ -L /usr/local/Cellar/boost/1.62.0/lib

[koksal]

Thanks @AmandaKedaigle !

[agitter]

Thanks @koksal for the advice. Commit 1a854b5 adds a link to this advice to the readme.