Repair the build of ide/coqidetop.cmxs (fix #4812)
Repair the build of ide/coqidetop.cmxs (fix #4812)

 Restore the .cmxa-->.cmxs rule from the Makefile. Sorry, I was thinking
 that all plugins would now be built from .mlpack (hence using only the
 .cmx-->.cmxs rule), and I forgot about this coqidetop business.

 Now the really intersting question is : why on earth 'make world' was
 silently failing to build this file but succeeding nonetheless ?!

Zimmi48/coq,JasonGross/coq,coq/coq,JasonGross/coq,william-lawvere/coq,letouzey/coq-wip,Ptival/coq,SkySkimmer/coq,Zimmi48/coq,Lionel-Rieg/coq,silene/coq,letouzey/coq-wip,ppedrot/coq,ejgallego/coq,JasonGross/coq,coq/coq,Matafou/coq,SkySkimmer/coq,ejgallego/coq,Matafou/coq,ejgallego/coq,amintimany/coq,silene/coq,mattam82/coq,mattam82/coq,Ptival/coq,Zimmi48/coq,maximedenes/coq,SkySkimmer/coq,Zimmi48/coq,maximedenes/coq,SkySkimmer/coq,coq/coq,ejgallego/coq,amintimany/coq,ppedrot/coq,gares/coq,maximedenes/coq,amintimany/coq,maximedenes/coq,ppedrot/coq,ppedrot/coq,william-lawvere/coq,Ptival/coq,mattam82/coq,letouzey/coq-wip,maximedenes/coq,gares/coq,gares/coq,Lionel-Rieg/coq,JasonGross/coq,letouzey/coq-wip,Matafou/coq,william-lawvere/coq,letouzey/coq-wip,gares/coq,gares/coq,ppedrot/coq,coq/coq,silene/coq,Lionel-Rieg/coq