Yacc files compiling with Xcode and native targets is broken...

Select your native target:
- show info and goto tab "Rules"
- add a new rule with the "+" button for processing Yacc source files
- enter the following custom script for compilation:
cd "$(DERIVED_FILE_DIR)/Yacc" && /usr/bin/yacc -d "$(INPUT_FILE_PATH)"

- add the following files as output files:
$(DERIVED_FILE_DIR)/Yacc/y.tab.h
$(DERIVED_FILE_DIR)/Yacc/y.tab.c

(create a separated line for each one using the "+" sign)