Arduino on Xcode Project — Official Thread

This is strange as your target is UNO.

I suggest you to edit the makefile on you project and add the names of the libraries to exclude:

# List the libraries to be excluded
# For example, WiFi may crash on Arduino 1.0.2
# For example, Esplora may crash on Arduino 1.0.3
# For example, Firmata may crash on Teensy 3.0
#
EXCLUDE_LIBS = Firmata WiFi WiFi/utility Esplora

It seems the Processing IDE is reaching its limits with the new Arduino products.

Thank you for reporting this issue. Please keep me informed of the result as I'm focused on the 1.5.x release