build: fix virthread build on mingw
build: fix virthread build on mingw

Our recent conversion to make VIR_ALLOC report oom wasn't
tested on mingw:

In file included from ../../src/util/virthread.c:29:0:
../../src/util/virthreadwin32.c: In function 'virCondWait':
../../src/util/virthreadwin32.c:166:81: error: 'VIR_FROM_THIS' undeclared (first use in this function)
     if (VIR_REALLOC_N(c->waiters, c->nwaiters + 1) < 0) {
                                                                                 ^

* src/util/virthreadwin32.c (VIR_FROM_THIS): Define.

Signed-off-by: Eric Blake <a9da18479c871fe903d9590822cfe2629c6a4d11@redhat.com>

fabianfreyer/libvirt,taget/libvirt,jardasgit/libvirt,taget/libvirt,jardasgit/libvirt,fabianfreyer/libvirt,eskultety/libvirt,zippy2/libvirt,shugaoye/libvirt,datto/libvirt,rlaager/libvirt,agx/libvirt,VenkatDatta/libvirt,nertpinx/libvirt,nertpinx/libvirt,jfehlig/libvirt,shugaoye/libvirt,andreabolognani/libvirt,jfehlig/libvirt,eskultety/libvirt,eskultety/libvirt,andreabolognani/libvirt,olafhering/libvirt,elmarco/libvirt,taget/libvirt,elmarco/libvirt,zippy2/libvirt,agx/libvirt,crobinso/libvirt,andreabolognani/libvirt,VenkatDatta/libvirt,crobinso/libvirt,cbosdo/libvirt,jfehlig/libvirt,nertpinx/libvirt,VenkatDatta/libvirt,andreabolognani/libvirt,libvirt/libvirt,shugaoye/libvirt,elmarco/libvirt,cbosdo/libvirt,rlaager/libvirt,olafhering/libvirt,libvirt/libvirt,crobinso/libvirt,shugaoye/libvirt,cbosdo/libvirt,jardasgit/libvirt,datto/libvirt,taget/libvirt,jardasgit/libvirt,zhlcindy/libvirt-1.1.4-maintain,jfehlig/libvirt,eskultety/libvirt,agx/libvirt,cbosdo/libvirt,fabianfreyer/libvirt,elmarco/libvirt,rlaager/libvirt,crobinso/libvirt,zhlcindy/libvirt-1.1.4-maintain,zhlcindy/libvirt-1.1.4-maintain,zippy2/libvirt,fabianfreyer/libvirt,nertpinx/libvirt,rlaager/libvirt,jardasgit/libvirt,zhlcindy/libvirt-1.1.4-maintain,datto/libvirt,cbosdo/libvirt,zippy2/libvirt,VenkatDatta/libvirt,elmarco/libvirt,libvirt/libvirt,rlaager/libvirt,agx/libvirt,taget/libvirt,olafhering/libvirt,andreabolognani/libvirt,eskultety/libvirt,fabianfreyer/libvirt,datto/libvirt,agx/libvirt,VenkatDatta/libvirt,libvirt/libvirt,datto/libvirt,zhlcindy/libvirt-1.1.4-maintain,shugaoye/libvirt,nertpinx/libvirt,olafhering/libvirt