affirm 132 maint/gnulib/lib/stack.h affirm (!_GL_STACK_PREFIX (empty) (stack)); affirm 141 maint/gnulib/lib/stack.h affirm (!_GL_STACK_PREFIX (empty) (stack)); affirm 150 maint/gnulib/lib/stack.h affirm (!_GL_STACK_PREFIX (empty) (stack));