Looking at the cross-platform nature of potrace http://potrace.sourceforge.net/, is it possible to compile this for iOS? If so, how?
Yes, it is possible to compile potrace for iOS.
As a matter of fact, most open source libraries using standard (GNU) configure tools that compile on MacOS X will easily compile on iOS, because they are likely free of platform-specific code (e.g. linuxisms) and standard configure tools allow cross-compilation.
You can compile these libraries in the shell by pointing configure to the proper toolchain and SDKs. Paths changed with Mavericks and Xcode 5, but fortunately automated scripts exist for more popular libraries such as expat.
The proposed solution is based on the x2on/expat-ios project on GitHub. Their script fixes expat's config.sub which doesn't know about arm64 target. Do does potrace 1.11's config.sub. However, a simpler approach consists in downloading a more recent version of config.sub. Unlike expat, potrace doesn't seem to need any patch to compile for iOS.
Full script build-potrace.sh is available here:
https://gist.github.com/pguyot/dce18af64a71b93c0204
Please note that potrace is licensed under the GPLv2. You might want to check Is it legal to publish iOS apps under the GNU GPLv3 open-source license? question.
来源：https://stackoverflow.com/questions/22702706/is-it-possible-to-compile-potrace-for-ios