In trunk - trunk there's a problem with BGRAControls, missing unit 'math'. I've fixed it in github.
Cross compiling from Windows 32 to Linux 64 gives me this:
Compile package BGRABitmapPack 9.9: Exit code 1, Errors: 7, Warnings: 5
bgragtkbitmap.pas(72,26) Error: Identifier not found "TGtk2DeviceContext"
bgragtkbitmap.pas(72,44) Error: Error in type definition
bgragtkbitmap.pas(124,36) Warning: unreachable code
bgragtkbitmap.pas(129,5) Error: Illegal type conversion: "HDC" to "TGtkDeviceContext"
bgragtkbitmap.pas(130,5) Error: Illegal type conversion: "HDC" to "TGtkDeviceContext"
bgragtkbitmap.pas(135,36) Warning: unreachable code
bgragtkbitmap.pas(310,38) Warning: unreachable code
bgragtkbitmap.pas(311,27) Error: Illegal type conversion: "HDC" to "TGtkDeviceContext"
bgragtkbitmap.pas(312,7) Error: Illegal type conversion: "HDC" to "TGtkDeviceContext"
bgragtkbitmap.pas(315,38) Warning: unreachable code
bgragtkbitmap.pas(353,5) Error: Illegal type conversion: "HDC" to "TGtkDeviceContext"
bgragtkbitmap.pas(355,36) Warning: unreachable code
Compile package IDEIntf 1.0: Aborted
Codetools, Errors: 1
bgragtkbitmap.pas(72,26) Error: identifier not found: TGtk2DeviceContext
Edit: I've seen there is a bug report about this, and it was solved removing the ifdef with everything inside, but anyways I don't have that change locally even if I'm using the dev branch.
Edit2: The fix is in the master branch, not in the dev branch...
And another edit: it works on Mac OS X as well with qt based IDE (maybe thanks to the bgracontrols fix as well)