* Fix msvcc dll build by adding dllexport decorations to all API declarations
* Fix appveyor build for VS 2013
Use the new -DFFI_BUILDING_DLL for producing a working DLL. Update the
msvcc.sh wrapper script to successfully compile the testsuite files.
* MSVC build: suppress warnings in testsuite
* fix testsuite on appveyor
af6773d6ab