I had to make the following change to the code to have it compile on OS X 10.9.5 with Xcode 6.2.

Index: CMakeLists.txt
===================================================================
--- CMakeLists.txt  (revision 228)
+++ CMakeLists.txt  (working copy)
@@ -36,7 +36,7 @@
 set(CMAKE_MODULE_LINKER_FLAGS_RELWITHDEBINFO "" CACHE INTERNAL "Unused")
 set(CMAKE_EXE_LINKER_FLAGS_RELWITHDEBINFO "" CACHE INTERNAL "Unused")

-set(CMAKE_OSX_ARCHITECTURES i386 ppc x86_64 CACHE STRING "change to needed architecture for a smaller library" FORCE)
+set(CMAKE_OSX_ARCHITECTURES i386 x86_64 CACHE STRING "change to needed architecture for a smaller library" FORCE)

 PROJECT(portmidi)