I did it like this:
Download Release v1.6.4d of fpcupdeluxe-x86_64-darwin-cocoa.zip
this file not have permiss for excecute
cd fpcupdeluxe-x86_64-darwin-cocoa.app/Contents/MacOS
sudo chmod +x fpcupdeluxe-x86_64-darwin-cocoa
run fpcupdeluxe-x86_64-darwin-cocoa.app
but not correct show setting
abort run fpcupdeluxe-x86_64-darwin-cocoa.app
open folder fpcupdeluxe-x86_64-darwin-cocoa.app/Contents/MacOS
and run with mouse fpcupdeluxe-x86_64-darwin-cocoa
Run is OK
Setting in cross CPU x86_64 and in OS Darwin
finally install fpc stable version
(Lazarus not install of fpcudeluxe)
Lazarus install with source code
in catalina not write in /usr/lib
for write
sudo mount -uw /
sudo ln -s /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk/usr/lib/crt1.10.5.o /usr/lib/crt1.10.5.o
cd fpcupdeluxe
mkdir lazarus
cd lazarus
svn checkout
https://svn.freepascal.org/svn/lazarus/branches/fixes_2_0 laz_fixes
// wait some time ....
cd laz_fixes
make LCL_PLATFORM=cocoa CPU_TARGET=x86_64 bigide
// wait some time .....
open startlazarus.app --args "--pcp=~/.laz_fixes"
Running
LaGuNa