spice: fix shared library build on clang
spice: fix shared library build on clang

- autoreconf for clang
- depend on libssp and winpthread-git
- explicitly link -lpthread as it was not getting linked in by -pthread.

Optiligence/MINGW-packages,InitialForce/MINGW-packages,Alexpux/MINGW-packages,jtanx/MINGW-packages,oscarfv/MINGW-packages,Optiligence/MINGW-packages,oroppas/MINGW-packages,stahta01/MINGW-packages,JPeterMugaas/MINGW-packages,oroppas/MINGW-packages,stahta01/MINGW-packages,Chocobo1/MINGW-packages,stahta01/MINGW-packages,jtanx/MINGW-packages,jtanx/MINGW-packages,Ede123/MINGW-packages,stahta01/MINGW-packages,Chocobo1/MINGW-packages,JPeterMugaas/MINGW-packages,Chocobo1/MINGW-packages,oscarfv/MINGW-packages,Ede123/MINGW-packages,JPeterMugaas/MINGW-packages,oroppas/MINGW-packages,Ede123/MINGW-packages,oroppas/MINGW-packages,fabiangreffrath/MINGW-packages,lhmouse/MINGW-packages,InitialForce/MINGW-packages,Alexpux/MINGW-packages,lhmouse/MINGW-packages,oroppas/MINGW-packages,stahta01/MINGW-packages,Optiligence/MINGW-packages,fabiangreffrath/MINGW-packages,lhmouse/MINGW-packages,fabiangreffrath/MINGW-packages,oscarfv/MINGW-packages,lhmouse/MINGW-packages,lhmouse/MINGW-packages,fabiangreffrath/MINGW-packages,Ede123/MINGW-packages,JPeterMugaas/MINGW-packages,stahta01/MINGW-packages,oscarfv/MINGW-packages,lhmouse/MINGW-packages,oroppas/MINGW-packages,InitialForce/MINGW-packages,JPeterMugaas/MINGW-packages,Optiligence/MINGW-packages,jtanx/MINGW-packages,oscarfv/MINGW-packages,oscarfv/MINGW-packages,JPeterMugaas/MINGW-packages,fabiangreffrath/MINGW-packages,Alexpux/MINGW-packages,Alexpux/MINGW-packages,fabiangreffrath/MINGW-packages,Alexpux/MINGW-packages,Alexpux/MINGW-packages