I'm getting this error when I run "make depend":
cd slapi; make -w depend
make[3]: Entering directory
`/vol01/developer/openldap/openldap-2.3.35/servers/slapd/slapi'
../../../build/mkdep -l -d "." -c "cc" -m "-M" -I../../../include -I..
-I. -I../../../include -I./.. -I. plugin.c slapi_pblock.c
slapi_utils.c printmsg.c slapi_ops.c slapi_dn.c slapi_ext.c slapi_overlay.c
plugin.c:32:18: ltdl.h: No such file or directory
make[3]: Leaving directory
`/vol01/developer/openldap/openldap-2.3.35/servers/slapd/slapi'