cross make buildworld error

[Danny Braniss]

trying to compile 5.2 on a 4.9 box:

...
mkdep -f .depend -a    -I/r+d/obj/dev/r+d/5.2/src/i386/legacy/usr/include 
-I/r+d/5.2/src/gnu/usr.bin/gperf/../../../contrib/gperf/lib -I/r+
d/5.2/src/gnu/usr.bin/gperf  /r+d/5.2/src/gnu/usr.bin/gperf/../../../contrib/gp
erf/src/bool-array.cc /r+d/5.2/src/gnu/usr.bin/gperf/../../.
./contrib/gperf/src/gen-perf.cc /r+d/5.2/src/gnu/usr.bin/gperf/../../../contrib
/gperf/src/hash-table.cc /r+d/5.2/src/gnu/usr.bin/gperf/../.
./../contrib/gperf/src/iterator.cc /r+d/5.2/src/gnu/usr.bin/gperf/../../../cont
rib/gperf/src/key-list.cc /r+d/5.2/src/gnu/usr.bin/gperf/../
../../contrib/gperf/src/list-node.cc /r+d/5.2/src/gnu/usr.bin/gperf/../../../co
ntrib/gperf/src/main.cc /r+d/5.2/src/gnu/usr.bin/gperf/../..
/../contrib/gperf/src/new.cc /r+d/5.2/src/gnu/usr.bin/gperf/../../../contrib/gp
erf/src/options.cc /r+d/5.2/src/gnu/usr.bin/gperf/../../../c
ontrib/gperf/src/read-line.cc /r+d/5.2/src/gnu/usr.bin/gperf/../../../contrib/g
perf/src/trace.cc /r+d/5.2/src/gnu/usr.bin/gperf/../../../co
ntrib/gperf/src/vectors.cc /r+d/5.2/src/gnu/usr.bin/gperf/../../../contrib/gper
f/src/version.cc /r+d/5.2/src/gnu/usr.bin/gperf/../../../con
trib/gperf/lib/hash.cc   
/r+d/5.2/src/gnu/usr.bin/gperf/../../../contrib/gperf/src/options.cc:24: 
getopt.h: No such file or directory
mkdep: compile failed
*** Error code 1
...