Just tried to set up cocoapods and ran into this error

checking for -std=c99 option to compiler... yes
checking for CoreFoundation... no
checking for main() in -lCoreFoundation... no
CoreFoundation is needed to build the Xcodeproj C extension.

Dislike. Finally found an answer that worked for me and didn’t resort to circumventing my homebrew / rvm setup, though it did involve installing a new ruby:

brew link autoconf
rvm install ruby-2.0.0-p353 --with-gcc=clang --verify-downloads 1
rvm use ruby-2.0.0-p353
gem install cocoapods

I’m sure this is all irrelevant if you use cocoapods, but I don’t (yet). My approach to installing SSZipArchive was to add it as a git submodule and drag the folder including SSZipArchive.h and minizip into my project, adding it by reference. This caused RestKit compilation to barf, mostly a lot of parse issues in RKURL.h like Expected identifier or '(', which is ridiculous b/c nothing changed in RestKit.

I eventually found my solution at http://stackoverflow.com/questions/9398409/adding-minizip-breaks-objective-c/18153812#18153812: change the file type of the minizip .c files to “Objective-C Source.”

Screen Shot 2013-09-24 at 3.15.51 PM

Now my project builds and everything works normally. Why this solution works is beyond my extremely limited knowledge of C and Xcode. These files look like C and/or C++, so why does telling Xcode to treat them like Objective-C even work?