I tried to build a 32bit FPC 3.2 (trunk / today svn) cross compile targe win-64

with the following opitons
OPT="-CX -gl -O4 -Or"

       Compiling .\fcl-db\src\json\fpjsondataset.pp        Compiling .\fcl-db\src\json\extjsdataset.pp        Compiling .\fcl-db\src\sqldb\sqldbini.pp [ 88%] Compiled package fcl-db
The installer encountered the following error:
Compilation of "BuildUnit_fcl_fpcunit.pp" failed
make.exe[2]: *** [all] Error 1
make.exe[2]: Leaving directory `c:/FPC/fpc_3.3.1/source/packages' make.exe[1]: *** [packages_all] Error 2
make.exe[1]: Leaving directory `c:/FPC/fpc_3.3.1/source' make.exe: *** [build-stamp.x86_64-win64] Error 2

The latest FPC trunk builds fine for me with your options. Both cross-compiling to win64 and native win64 build.

Check if the error occurs after "make distclean"
If it still fails try to update sources to r45001 and test the building.

Yuriy.