Bug#1094386: openldap FTCBFS: uses the build architecture compiler

[Ryan Tandy]

Cross-built slapd doesn't work. slapd is linked without -export-dynamic, 
I think because LT_SYS_DLOPEN_SELF returns "cross". Then modules fail to 
load, because slapd doesn't export the symbols they need; e.g. back_mdb 
misses dnRelativeMatch. I guess slapd has to be <!cross>.

I think cross-built libldap is ok? Basic ldapsearch seems to work...