IRIX 6.3's as doesn't like #line directives

[Alexandre Oliva]

"/home/msc/oliva/src/libgcj-2.95/boehm-gc/mips_sgi_mach_dep.s", line 1: error(1014):
          extra text after expected end of preprocessing directive
  # 1 "/usr/include/sys/regdef.h" 1 3
                                    ^

This patch gets us rid of them: