Don't know if the various makes are smart enough to only use the SEH for Win64 cross compiling on your machine
However, on my Win64 machine, I did this:
Parameter list: --binutilsdir="c:\development\fpcbootstrap64" --fpcboots
trapdir="c:\development\fpcbootstrap64" --fpcdir="c:\development\fpctrunk" --laz
dir="c:\development\lazarus64_fpctrunk" --fpcuplinkname="" --fpcOPT="-gw -gl -dT
EST_WIN64_SEH" --keeplocalchanges --lazlinkname="Laz64FPCTrunk" --lazOPT="-gw -g
l" --primary-config-path="c:\development\lazarus64settings_fpctrunk" --noconfirm
--fpcURL="http://svn.freepascal.org/svn/fpc/trunk" --verbose
with development fpcup:
fpcup 19d28898dcca (Tue Dec 18 09:04:16 2012 +0100)
... and it give this result
The installer encountered the following error:
External command "C:/development/fpctrunk/compiler/ppcx64.exe -Twin64 -FUfcl-stl
\units\x86_64-win64\ -FuC:\development\fpctrunk\rtl\units\x86_64-win64\ -Fufcl-s
tl\src -Ur -Xs -O2 -n -FuC:/development/fpctrunk/rtl/units/x86_64-win64 -gw -gl
-dTEST_WIN64_SEH -dx86_64 -dRELEASE -S2h -viq fcl-stl\BuildUnit_fcl_stl.pp" fail
ed with exit code 1. Console output:
Target OS: Win64 for x64
Compiling fcl-stl\BuildUnit_fcl_stl.pp
Compiling .\fcl-stl\src\garrayutils.pp
Compiling .\fcl-stl\src\gdeque.pp
Compiling .\fcl-stl\src\gset.pp
Compiling .\fcl-stl\src\gmap.pp
Compiling .\fcl-stl\src\gvector.pp
Compiling .\fcl-stl\src\gpriorityqueue.pp
Compiling .\fcl-stl\src\gqueue.pp
Compiling .\fcl-stl\src\gtree.pp
Compiling .\fcl-stl\src\gstack.pp
gtree.pp(88,4) Error: Generic methods cannot have nested procedures
gtree.pp(118,4) Error: Generic methods cannot have nested procedures
gtree.pp(136,4) Error: Generic methods cannot have nested procedures
gtree.pp(140) Fatal: There were 3 errors compiling module, stopping
Fatal: Compilation aborted
.... so I see the same problem.
Perhaps due to recent changes in fcl-stl...