I thought I’d throw this info out there for those of you using Mac OS X and either want to compile your own or are having problems with some of the core compiles. Here’s my experience with 10.8 and 10.7 using the latest Xcode and MacPorts. I’m not really able to do any troubleshooting if anybody is having problems, this is just a guide as to how I was able to get everything to work. Names in parenthesis next to package names are the actual names that MacPorts uses, this will make it easier to find and install them.
RetroArch Notes: Install ffmpeg (ffmpeg), libsdl (libsdl), pkgconfig (pkgconfig), freetype (freetype), libxml2 (libxml2), and sdlimage (libsdl_image) from MacPorts. Install Nvidia CG Toolkit from Nvidia’s website. The compilation guide mentions GCC 4.6 as a requirement but I have been able to build just fine with the latest Clang supplied with Xcode. Build as instructed on the compilation guide. ffmpeg, freetype, libxml2, sdlimage and the Nvidia CG Toolkit are all optional, you will want them though for the follwing features: ffmpeg: recording movies, freetype: option to change fonts, libxml2: allows you to use XML shaders and cheats, sdlimage: I believe this is used for screenshots?, Nvidia CG Toolkit: this gives you the ability to use CG shaders, one of the more powerful features of RetroArch!
RetroArch-Phoenix
Notes: Compiles cleanly after the following: Install GCC 4.6 (gcc46) and QT4 (qt4-mac) from MacPorts. Temporarily change your compiler to GCC 4.6 to build, the command is as follows: “sudo port select --set gcc mp-gcc46” to revert after building use the following command “sudo port select --set gcc none”. Google it for more info if you’re not sure what you’re doing 
Here are the cores that I’ve compiled and any relevant notes, anything not listed I have not tried and have no insight on them:
bnes_libretro Notes: Requires GCC 4.6 or 4.7 to compile, it will not compile with Clang. Change your compiler just as you need to for RetroArch-Phoenix compilation. Delete “-Wl,–no-undefined” from line 66 in the Makefile before building.
bsnes_libretro Notes: Compiles cleanly.
desmume_libretro Notes: Compiles cleanly.
dosbox_libretro Notes: Compiles cleanly.
fb_alpha_libretro Notes: Compiles cleanly.
gambatte_libretro Notes: Compiles cleanly.
genesis_plus_gx_libretro Notes: Compiles cleanly.
higan_accuracy_libretro Notes: Compiles cleanly, pull from the following Git repository: “git://gitorious.org/bsnes/bsnes.git”, compile with the following command: “make ui=target-libretro profile=performance”. Look to the “libretro-super” repository and scripts for more insight.
higan_balanced_libretro Notes: Compiles cleanly, pull from the following Git repository: “git://gitorious.org/bsnes/bsnes.git”, compile with the following command: “make ui=target-libretro profile=balanced”. Look to the “libretro-super” repository and scripts for more insight.
higan_performance_libretro Notes: Compiles cleanly, pull from the following Git repository: “git://gitorious.org/bsnes/bsnes.git”, compile with the following command: “make ui=target-libretro profile=accuracy”. Look to the “libretro-super” repository and scripts for more insight.
mednafen-libretro mednafen_gba_libretro mednafen_lynx_libretro mednafen_ngp_libretro mednafen_pce_fast_libretro mednafen_pcfx_libretro mednafen_psx_libretro mednafen_snes_libretro mednafen_wswan_libretro Notes: All compile cleanly with the exception of mednafen_snes_libretro, which requires GCC 4.6 or 4.7, it will not compile with Clang. Change your compiler just as you need to for RetroArch-Phoenix compilation.
meteor_libretro Notes: Compiles cleanly.
nestopia_libretro Notes: Requires GCC 4.6 or 4.7 to compile, it will not compile with Clang. Change your compiler just as you need to for RetroArch-Phoenix compilation.
snes9x_150 Notes: Compiles cleanly.
snes9x_next_libretro Notes: Compiles cleanly.
vba_next_libretro Notes: Compiles cleanly.
yabause_libretro Notes: Compiles cleanly.
Other notes: I look to the “libretro-super” repository from time to time to help compile when I run into issues as it has additional insight if you dig into it. The Higan cores are not listed in the libretro repository but are pulled from a different spot, again, the insight came from the libretro-super scripts.
If anybody was able to get a recent version of the fceu-next libretro coreto compile for OS X, let me know how you did it! Older versions had no problems, but now I get compilation errors with every compiler I’ve tried (GCC 4.2, 4.6, 4.7, Clang (supplied with Xcode), llvm-gcc42).
Thanks!