[Lazarus] How is work search path in CrossPlatform

[FreeMan]

> That's the easy part. The package uses the target of the project. Set
> the project to win32 and the needed Lazarus packages will automatically
> be compiled for win32 too.

I have no different way, I asked,  can add, if just lpk is opened, and 
lpk's compiler options enabled select target os & cpu and etc. And we 
can click just compile and selected os and cpu been compiled. Not all 
project and all other packages have to compile. I have ssd so I have to 
thing write count on disk :)
I can not answer mu self, for hiding target os and cpu options on 
package's options. Install menu can be disable if IDE's and target os is 
diffrent. this is my idea.
I can estimate answer :)  create new empty project and one form, add to 
my package to dependency select wich os you want :)

> {$IFDEF Linux}
>    x
>    {$ELSE}
>    Windows
>    {$ENDIF}
>    ;

where I can find this equivalent list? I mean X-server in linux equal 
Windows unit in windows, xxx  in  mac os etc ? because I didn't test in 
mac os but its in my near future plan, I will need it.
activex as well

Thank you.