Make distribution error

Dear all,

Why does below error always appear when I type "make distribution" in
CURRENT source from existing 6.1-PRERELEASE

"/tmp/hd/usr/src/etc/Makefile", line 59: if-less endif
"/tmp/hd/usr/src/etc/Makefile", line 60: if-less endif
"/tmp/hd/usr/src/etc/Makefile", line 62: Malformed conditional
(${MK_BIND_ETC} != "no")
"/tmp/hd/usr/src/etc/Makefile", line 65: if-less endif
"/tmp/hd/usr/src/etc/Makefile", line 69: Malformed conditional
(${MK_SENDMAIL} == "no")
"/tmp/hd/usr/src/etc/Makefile", line 71: if-less else
"/tmp/hd/usr/src/etc/Makefile", line 74: if-less endif
"/tmp/hd/usr/src/etc/Makefile", line 80: Malformed conditional (${MK_MAN} !=
"no")
"/tmp/hd/usr/src/etc/Makefile", line 82: if-less endif
"/tmp/hd/usr/src/etc/Makefile", line 130: Malformed conditional (${MK_I4B}
!= "no")
"/tmp/hd/usr/src/etc/Makefile", line 132: if-less endif
"/tmp/hd/usr/src/etc/Makefile", line 133: Malformed conditional
(${MK_SENDMAIL} != "no"