coqchk: don't marshal opaques for dependencies of -norec libraries
coqchk: don't marshal opaques for dependencies of -norec libraries

About 20% better perf on test-suite/arithmetic/mod (3.4s to 2.6s)

ejgallego/coq,coq/coq,Matafou/coq,JasonGross/coq,ppedrot/coq,coq/coq,ppedrot/coq,ejgallego/coq,ejgallego/coq,silene/coq,ppedrot/coq,Zimmi48/coq,Zimmi48/coq,gares/coq,SkySkimmer/coq,ppedrot/coq,JasonGross/coq,Zimmi48/coq,ejgallego/coq,Zimmi48/coq,coq/coq,SkySkimmer/coq,Matafou/coq,coq/coq,SkySkimmer/coq,JasonGross/coq,JasonGross/coq,Matafou/coq,ppedrot/coq,gares/coq,gares/coq,SkySkimmer/coq,gares/coq,silene/coq,gares/coq,silene/coq