curl: enable MultiSSL mode by enabling WinSSL (#3055)
curl: enable MultiSSL mode by enabling WinSSL (#3055)

In both the openssl and gnutls variants. MultiSSL has
been introduced in curl 7.56.0 and allows multiple
SSL backends to be linked at the same time. It's then
possible to select between them at runtime.

Ref: https://curl.haxx.se/libcurl/c/curl_global_sslset.html
Ref: https://github.com/curl/curl/commit/1328f69d53f2f2e937696ea954c480412b018451

Also fix quote in --with-nghttp2= option.
bjlemke/MINGW-packages,KrullKorg/MINGW-packages,mashir43/MINGW-packages,git-for-windows/MINGW-packages,Ede123/MINGW-packages,InitialForce/MINGW-packages,fabiangreffrath/MINGW-packages,dsogari/MINGW-packages,zklhp/MINGW-packages,jtanx/MINGW-packages,dscho/MINGW-packages,fabiangreffrath/MINGW-packages,stahta01/MINGW-packages,stambaughw/MINGW-packages,Alexpux/MINGW-packages,git-for-windows/MINGW-packages,jeroenooms/MINGW-packages,JPeterMugaas/MINGW-packages,oscarfv/MINGW-packages,fabiangreffrath/MINGW-packages,signotorez/MINGW-packages,oroppas/MINGW-packages,JPeterMugaas/MINGW-packages,int19h/MINGW-packages,Optiligence/MINGW-packages,Chocobo1/MINGW-packages,JPeterMugaas/MINGW-packages,Ede123/MINGW-packages,juergenpf/MINGW-packages,dscho/MINGW-packages,emmenlau/MINGW-packages,fabiangreffrath/MINGW-packages,JPeterMugaas/MINGW-packages,jtanx/MINGW-packages,mashir43/MINGW-packages,irakhlin/MINGW-packages,lhmouse/MINGW-packages,mati865/MINGW-packages,lhmouse/MINGW-packages,irakhlin/MINGW-packages,InitialForce/MINGW-packages,stahta01/MINGW-packages,stambaughw/MINGW-packages,int19h/MINGW-packages,KrullKorg/MINGW-packages,Optiligence/MINGW-packages,Alexpux/MINGW-packages,dsogari/MINGW-packages,RickLeaf/MINGW-packages,oscarfv/MINGW-packages,peterbud/MINGW-packages,juergenpf/MINGW-packages,RickLeaf/MINGW-packages,oroppas/MINGW-packages,zklhp/MINGW-packages,nazar554/MINGW-packages,mashir43/MINGW-packages,juergenpf/MINGW-packages,Optiligence/MINGW-packages,stahta01/MINGW-packages,qme/MINGW-packages,stambaughw/MINGW-packages,zklhp/MINGW-packages,jeroenooms/MINGW-packages,nickoe/MINGW-packages,dscho/MINGW-packages,mashir43/MINGW-packages,oscarfv/MINGW-packages,KrullBorg/MINGW-packages,bjlemke/MINGW-packages,Optiligence/MINGW-packages,KrullBorg/MINGW-packages,fabiangreffrath/MINGW-packages,mati865/MINGW-packages,stahta01/MINGW-packages,KrullKorg/MINGW-packages,dscho/MINGW-packages,nickoe/MINGW-packages,Alexpux/MINGW-packages,KrullBorg/MINGW-packages,dscho/MINGW-packages,mati865/MINGW-packages,oroppas/MINGW-packages,stahta01/MINGW-packages,nickoe/MINGW-packages,Alexpux/MINGW-packages,peterbud/MINGW-packages,lhmouse/MINGW-packages,Chocobo1/MINGW-packages,lhmouse/MINGW-packages,Ede123/MINGW-packages,JPeterMugaas/MINGW-packages,juergenpf/MINGW-packages,oroppas/MINGW-packages,lhmouse/MINGW-packages,qme/MINGW-packages,fabiangreffrath/MINGW-packages,oscarfv/MINGW-packages,oroppas/MINGW-packages,filnet/MINGW-packages,bjlemke/MINGW-packages,irakhlin/MINGW-packages,emmenlau/MINGW-packages,lhmouse/MINGW-packages,peterbud/MINGW-packages,peterbud/MINGW-packages,JPeterMugaas/MINGW-packages,nazar554/MINGW-packages,oscarfv/MINGW-packages,qme/MINGW-packages,signotorez/MINGW-packages,int19h/MINGW-packages,InitialForce/MINGW-packages,nazar554/MINGW-packages,jeroenooms/MINGW-packages,dsogari/MINGW-packages,emmenlau/MINGW-packages,filnet/MINGW-packages,nazar554/MINGW-packages,RickLeaf/MINGW-packages,Alexpux/MINGW-packages,stahta01/MINGW-packages,jtanx/MINGW-packages,KrullBorg/MINGW-packages,signotorez/MINGW-packages,filnet/MINGW-packages,mati865/MINGW-packages,git-for-windows/MINGW-packages,int19h/MINGW-packages,Alexpux/MINGW-packages,bjlemke/MINGW-packages,mati865/MINGW-packages,Ede123/MINGW-packages,irakhlin/MINGW-packages,RickLeaf/MINGW-packages,oscarfv/MINGW-packages,qme/MINGW-packages,jtanx/MINGW-packages,Chocobo1/MINGW-packages,oroppas/MINGW-packages