change to ubuntu 20.04 and kernel 5.9

compile.bash

@@ -2,22 +2,22 @@
 
 # get current kernel and realtime patch version
 
-FILE=`curl -s https://mirrors.edge.kernel.org/pub/linux/kernel/projects/rt/5.4/`
-KERNEL=`echo $FILE | sed -n 's/.*patch-5.4.\(.*\)-rt.*.patch.gz.*/\1/p'`
-RTPATCH=`echo $FILE | sed -n 's/.*patch-5.4..*-rt\(.*\).patch.gz.*/\1/p'`
-echo "using kernel 5.4.$KERNEL with realtime patch $RTPATCH"
+FILE=`curl -s https://mirrors.edge.kernel.org/pub/linux/kernel/projects/rt/5.9/`
+KERNEL=`echo $FILE | sed -n 's/.*patch-5.9.\(.*\)-rt.*.patch.gz.*/\1/p'`
+RTPATCH=`echo $FILE | sed -n 's/.*patch-5.9..*-rt\(.*\).patch.gz.*/\1/p'`
+echo "using kernel 5.9.$KERNEL with realtime patch $RTPATCH"
 
 # get kernel file names and location
 
 KERNELURL=https://www.kernel.org/pub/linux/kernel/v5.x/
-KERNELNAME=linux-5.4.${KERNEL}
-KERNELFILE=linux-5.4.${KERNEL}.tar
-KERNELFILEXZ=linux-5.4.${KERNEL}.tar.xz
-KERNELSIGN=linux-5.4.${KERNEL}.tar.sign
-PATCHURL=https://www.kernel.org/pub/linux/kernel/projects/rt/5.4/
-PATCHFILE=patch-5.4.${KERNEL}-rt${RTPATCH}.patch
-PATCHFILEXZ=patch-5.4.${KERNEL}-rt${RTPATCH}.patch.xz
-PATCHSIGN=patch-5.4.${KERNEL}-rt${RTPATCH}.patch.sign
+KERNELNAME=linux-5.9.${KERNEL}
+KERNELFILE=linux-5.9.${KERNEL}.tar
+KERNELFILEXZ=linux-5.9.${KERNEL}.tar.xz
+KERNELSIGN=linux-5.9.${KERNEL}.tar.sign
+PATCHURL=https://www.kernel.org/pub/linux/kernel/projects/rt/5.9/
+PATCHFILE=patch-5.9.${KERNEL}-rt${RTPATCH}.patch
+PATCHFILEXZ=patch-5.9.${KERNEL}-rt${RTPATCH}.patch.xz
+PATCHSIGN=patch-5.9.${KERNEL}-rt${RTPATCH}.patch.sign
 
 # download kernel
 
@@ -46,7 +46,7 @@ patch -p1 < ../${PATCHFILE}
 
 # build the kernel
 
-# use the kernel config build on a normal ubuntu 18.4
+# use the kernel config build on a normal ubuntu 20.4
 cp ../config .config
 # update config with defaults if new options have been added
 make olddefconfig