1. Edit the Makefile.
   In most cases it should suffice to set three variables: DEBUG; ASSEMBLER;
   ARCH.

2. Run 'make'.
   This should produce one executable: gcwsieve.


Note that when compiling sieve.c for x86 architectures with ASSEMBLER=yes,
warnings similar to the following are normal and can be ignored:
  /tmp/ccM6vgA2.s: Assembler messages:
  /tmp/ccM6vgA2.s:585: Warning: missing operand; zero assumed
