Hi Jim, Christian,

I can report success building on OS X, but there were a few config details that had to be ironed out to get everything to work.

First, to build externals-clasp, in local.config.darwin, the capitalization “darwin” disagrees with the makefile, which checks for “Darwin”, which is easy to fix:

export TARGET_OS = Darwin

Since clasp asks for gcc >= 4.8, I also set gcc/g++ variables to a newer version installed from brew:

export GCC_EXECUTABLE = /usr/local/bin/gcc-4.9
export GXX_EXECUTABLE = /usr/local/bin/g++-4.9

To build clasp, the directions for setting up local.config didn’t quite work for me. I had to do the following:

export TOOLSET = clang-darwin

rather than just “clang”, which is suggested in clasp/README.md. This was also just changed to agree with the makefile.

Built with make clean; make, copied to /Applications, and the executable at /Applications/clasp/Contents/execs/boehm/release/bin/clasp ran the first time.

Hope that’s helpful,

Sky Hester


On Apr 16, 2016, at 8:05 AM, Christian Schafmeister <chris.schaf@verizon.net> wrote:

Thanks Jim,

I updated the info here to explain how to build on OS X.

Could you tell me how it goes?


On Apr 11, 2016, at 5:40 AM, Jim Newton <jnewton@lrde.epita.fr> wrote:

I’m trying to get started with Clasp.   I cloned a copy of the git repo.

I looked at the README.md file instructions.  First it says to try to download a precompiled release from
But when I look on that web page it says:
Please do not use the "source code" downloads below; clone the repository instead,


OK, so maybe the README.md is out of date?
So I though about trying to compile it myself.

The README.md file says to follow an extra step for Mac detailed on the page
But I really don’t understand what that page is telling me to do.
Here’s what I read there.

Building Clasp on OS X requires using the same version of Clang that Clasp is linked with. I use the llvm/clang version that gets built by externals-clasp.

This clang needs to be informed where OS X compiler resources (header files) are located.

So the following symbolic link needs to be installed.

Let's say the external clang executable is installed at /Users/meister/Development/externals-clasp/build/release/bin/clang.


Questions:  Am I supposed to understand which version of Clang Clasp is linked with?  Especially before I’ve compiled
the first time?  What is “external clang”?   I see that on my system clang is in /usr/bin/clang.   Do I need to install another clang?

If someone could give me some more help, that’d be great.

Kind regards
Jim