Shouldn't world be able to build without /usr/include?

[Doug Barton]

===> tools/build (obj,includes,depend,all,install)
grep: /usr/include/stdio.h: No such file or directory
/usr/obj/frontier/svn/head/tmp/frontier/svn/head/tools/build created for
/frontier/svn/head/tools/build
grep: /usr/include/stdio.h: No such file or directory
cd /frontier/svn/head/tools/build; make buildincludes; make installincludes
grep: /usr/include/stdio.h: No such file or directory
grep: /usr/include/stdio.h: No such file or directory
grep: /usr/include/stdio.h: No such file or directory
grep -v HAVE_GETLINE
/frontier/svn/head/tools/build/../../lib/libmagic/config.h > config.h
rm -f .depend
mkdep -f .depend -a    -DHAVE_CONFIG_H -I.
-I/usr/obj/frontier/svn/head/tmp/legacy/usr/include -std=gnu99
/frontier/svn/head/tools/build/../../contrib/file/getline.c
In file included from
/frontier/svn/head/tools/build/../../contrib/file/getline.c:32:
/frontier/svn/head/tools/build/../../contrib/file/file.h:52:74: error:
stdio.h: No such file or directory
/frontier/svn/head/tools/build/../../contrib/file/file.h:53:19: error:
errno.h: No such file or directory
/frontier/svn/head/tools/build/../../contrib/file/file.h:54:44: error:
fcntl.h: No such file or directory
/frontier/svn/head/tools/build/../../contrib/file/file.h:59:20: error:
stdint.h: No such file or directory
/frontier/svn/head/tools/build/../../contrib/file/file.h:62:22: error:
inttypes.h: No such file or directory
/frontier/svn/head/tools/build/../../contrib/file/file.h:64:19: error:
regex.h: No such file or directory
/frontier/svn/head/tools/build/../../contrib/file/file.h:65:23: error:
sys/types.h: No such file or directory
/frontier/svn/head/tools/build/../../contrib/file/file.h:66:23: error:
sys/param.h: No such file or directory
/frontier/svn/head/tools/build/../../contrib/file/file.h:68:22: error:
sys/stat.h: No such file or directory
/frontier/svn/head/tools/build/../../contrib/file/file.h:69:20: error:
stdarg.h: No such file or directory
/frontier/svn/head/tools/build/../../contrib/file/getline.c:34:20:
error: stdlib.h: No such file or directory
/frontier/svn/head/tools/build/../../contrib/file/getline.c:36:20:
error: unistd.h: No such file or directory
/frontier/svn/head/tools/build/../../contrib/file/getline.c:38:20:
error: string.h: No such file or directory
mkdep: compile failed
*** [.depend] Error code 1



-- 

    I am only one, but I am one.  I cannot do everything, but I can do
    something.  And I will not let what I cannot do interfere with what
    I can do.
			-- Edward Everett Hale, (1822 - 1909)