Used gcc46. Output: ... error: variable '...' set but not used [-Werror=unused-but-set-variable] cc1: all warnings being treated as errors Makefile should be appened with either CONFIGURE_ARGS= --disable-werror or CFLAGS +=-Wno-error -Wno-unused-parameter -Wno-unused-but-set-variable -Wno-unused-variable -Wno-unused-value or both even.