Defines starting with `n' in bsd/ppc

• NBPG bsd/ppc/param.h:40
• NBSEG bsd/ppc/param.h:44
• NIOPIDS bsd/ppc/param.h:136
• NMAGIC bsd/ppc/exec.h:78
• NMBCLUSTERS bsd/ppc/param.h:75
• NPIDS bsd/ppc/param.h:135