qemu_capabilities: Introduce virQEMUCapsGetDefaultMachine

Sometimes it may be useful to get a default machine for given qemu
binary. Fortunately, the default machine is stored always on the first
position in the supported machines array.

Signed-off-by: Michal Privoznik <mprivozn@redhat.com>

src/qemu/qemu_capabilities.c

@@ -3556,3 +3556,12 @@ virQEMUCapsIsMachineSupported(virQEMUCapsPtr qemuCaps,
     }
     return false;
 }
+
+
+const char *
+virQEMUCapsGetDefaultMachine(virQEMUCapsPtr qemuCaps)
+{
+    if (!qemuCaps->nmachineTypes)
+        return NULL;
+    return qemuCaps->machineTypes[0];
+}

src/qemu/qemu_capabilities.h

@@ -305,6 +305,8 @@ bool virQEMUCapsSupportsChardev(virDomainDefPtr def,
 bool virQEMUCapsIsMachineSupported(virQEMUCapsPtr qemuCaps,
                                    const char *canonical_machine);
 
+const char * virQEMUCapsGetDefaultMachine(virQEMUCapsPtr qemuCaps);
+
 int virQEMUCapsInitGuestFromBinary(virCapsPtr caps,
                                    const char *binary,
                                    virQEMUCapsPtr qemubinCaps,