gistfile1.txt

$ make clean
$ ruby extconf.rb
checking for float.h... yes
checking for ruby.h... yes
checking for stdlib.h... yes
checking for string.h... yes
checking for fcntl.h... yes
checking for sys/errno.h... yes
checking for sys/socket.h... yes
checking for ruby/st.h... yes
checking for st.h... yes
checking for pthread_create() in -lpthread... yes
creating Makefile
$ grep 'CC =' Makefile
CC = gcc-4.2
$ make
compiling ext.c
compiling match.c
compiling matcher.c
compiling watchman.c
linking shared-object ext.bundle
$ make clean
$ CC=clang ruby extconf.rb
checking for float.h... yes
checking for ruby.h... yes
checking for stdlib.h... yes
checking for string.h... yes
checking for fcntl.h... yes
checking for sys/errno.h... yes
checking for sys/socket.h... yes
checking for ruby/st.h... yes
checking for st.h... yes
checking for pthread_create() in -lpthread... yes
creating Makefile
$ grep 'CC =' Makefile
CC = clang
$ make
compiling ext.c
compiling match.c
compiling matcher.c
compiling watchman.c
linking shared-object ext.bundle