で、/usr/objも消して/usr/srcも消して
あらためてやってみたのだが

cc -O2 -fno-strict-aliasing -pipe -I. -I/usr/src/usr.bin/xlint/lint1
-I/usr/src/usr.bin/xlint/lint1/../arch/amd64
-I/usr/src/usr.bin/xlint/lint1/../common -I/usr/obj/usr/src/tmp/legacy/usr/include -c cgram.c
yacc: 1 shift/reduce conflict
cc -O2 -fno-strict-aliasing -pipe -I. -I/usr/src/usr.bin/xlint/lint1
-I/usr/src/usr.bin/xlint/lint1/../arch/amd64
-I/usr/src/usr.bin/xlint/lint1/../common
-I/usr/obj/usr/src/tmp/legacy/usr/include -c scan.c
cc -O2 -fno-strict-aliasing -pipe -I. -I/usr/src/usr.bin/xlint/lint1
-I/usr/src/usr.bin/xlint/lint1/../arch/amd64
-I/usr/src/usr.bin/xlint/lint1/../common
-I/usr/obj/usr/src/tmp/legacy/usr/include -c /usr/src/usr.bin/xlint/lint1/tree.c
cgram.c:312:21: warning: no newline at end of file
cgram.c:312: error: syntax error at end of input
cgram.c:267: warning: array 'yydefred' assumed to have one element
*** Error code 1
1 error
*** Error code 2
1 error
*** Error code 2
1 error
*** Error code 2
1 error

なんじゃこれ・・・
またsysinstallからやるか