The problem is that the wrong function signature is used,
need to use,
RooAbsPdf* bindPdf(TF1* func, RooAbsReal& x)
not
BUT, the confusing bit,
The correct signature is not found if the RooFit library is loaded after RooFit is imported. Related post: Where are the RooFit::bindFunction()s in PyRoot?
Corrected code, note order in import statements,
from ROOT import gSystem
gSystem.Load( "libRooFit" )
from ROOT import RooFit, RooRealVar
from ROOT import TF1
from ROOT import RooFit, RooWorkspace, RooArgList, RooRealVar #@UnusedImport @UnresolvedImport
fcn = TF1('fcn', 'sin(x)/x', 0, 10)
x = RooRealVar('x', 'x', 0, 10)
roofcn = RooFit.bindPdf(fcn, x)
print roofcn