Added vfat support to mount /dev/archiso

fstype from klibc don't detect a vfat formatted blockdevice when try to
mount /dev/archiso to /bootmnt. Some users don't use the recommened
method with dd to bring the image to their USB stick. If they for ex.
use Unetbootin to put the iso image on their (v)fat formatted stick they
got lost with a kernel panic cause fstype won't detect vfat, so the
mount and the later squashfs bindings traps.

Signed-off-by: Gerhard Brauer <gerbra@archlinux.de>

archiso/hooks/archiso

@@ -64,20 +64,31 @@ run_hook ()
     done
 
     eval $(fstype < /dev/archiso 2>/dev/null)
-    if [ -n "${FSTYPE}" -a "${FSTYPE}" != "unknown" ]; then
-      if mount -r -t "${FSTYPE}" /dev/archiso /bootmnt >/dev/null 2>&1; then
-        if [ -e "/bootmnt/isomounts" ]; then
-          echo "SUCCESS: Mounted archiso volume successfully."
+    if [ -n "${FSTYPE}" ]; then
+        if [ "${FSTYPE}" = "unknown" ]; then
+            # First try mounting then with vfat, maybe someone put the image on
+            # USB stick with unetbootin or similar. vfat is not detected by fstype.
+            _FSTYPE="vfat"
         else
-          echo "ERROR: Mounting was successful, but the isomounts file does not exist."
-          exit 1
+            _FSTYPE=$FSTYPE
+        fi
+        if mount -r -t "${_FSTYPE}" /dev/archiso /bootmnt >/dev/null 2>&1; then
+            if [ -e "/bootmnt/isomounts" ]; then
+                echo "SUCCESS: Mounted archiso volume successfully."
+            else
+                echo "ERROR: Mounting was successful, but the isomounts file does not exist."
+                exit 1
+            fi
+        else
+            if [ "${FSTYPE}" = "unknown" ]; then
+                echo "ERROR: Failed to mount /dev/archiso (FS is unknown and not vfat)."
+            else
+                echo "ERROR; Failed to mount /dev/archiso (FS is ${FSTYPE}."
+            fi
+            exit 1
         fi
-      else
-        echo "ERROR: Failed to mount /dev/archiso"
-        exit 1
-      fi
     else
-      echo "ERROR: /dev/archiso found, but the filesystem type is unknown."
+        echo "ERROR: /dev/archiso found, but the filesystem type is unknown."
     fi
 
     /bin/modprobe -q squashfs >/dev/null 2>&1