Fetch -rc kernels via git using qubesbuilder

Getting tarball hash is not needed anymore, qubesbuilderv2 can take care
of git tag verification.

Author: marmarek

.qubesbuilder

@@ -12,13 +12,13 @@ source:
   - url: https://cdn.kernel.org/pub/linux/kernel/v6.x/linux-@[email protected]
     signature: https://cdn.kernel.org/pub/linux/kernel/v6.x/linux-@[email protected]
     uncompress: true
+## for -rc kernels, use this:
+#  - git-url: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
+#    git-basename: linux-@VERSION@
+#    tag: v@VERSION@
     pubkeys:
     - kernel.org-2-key.asc
     - kernel.org-1-key.asc
-## for -rc kernels, use this:
-#  - url: https://git.kernel.org/torvalds/t/linux-@[email protected]
-#    uncompress: true
-#    sha256: linux-@[email protected]
 #  - url: https://github.com/PatrickVerner/macbook12-spi-driver/archive/2905d318d1a3ee1a227052490bf20eddef2592f9.tar.gz#/macbook12-spi-driver-2905d318d1a3ee1a227052490bf20eddef2592f9.tar.gz
 #    uncompress: true
 #    sha256: macbook12-spi-driver-2905d318d1a3ee1a227052490bf20eddef2592f9.tar.sha256

README.md

@@ -5,18 +5,4 @@ Building release candidate kernels
 ----------------------------------
 
 1. Write kernel version into `version` file, for example 6.0-rc7.
-2. Write hash of `linux-*.tar` file (the uncompressed source tarball) into `linux-*.tar.sha256` file.
-3. Comment out "normal" tarball section in `.qubesbuilder` and uncomment the one for rc kernel.
-
-
-As for getting the trustworthy tarball hash, it can be via signed git tag:
-
-```
-version=6.0-rc7
-git clone -n --depth=1 https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git -b v$version linux-rc
-cd linux-rc
-git verify-tag v$version
-# should be signed by Linus, you can find key in kernel.org-1-key.asc
-git archive --prefix=linux-$version/ v$version | sha256sum
-```
-
+2. Comment out "normal" tarball section in `.qubesbuilder` and uncomment the one for rc kernel.

kernel.spec.in

@@ -120,7 +120,11 @@ Provides:       kernel-uname-r = %kernelrelease
 
 ExclusiveArch:  x86_64
 
+%if %prerelease
+Source0:        linux-%{upstream_version}.tar.gz
+%else
 Source0:        linux-%{upstream_version}.tar
+%endif
 Source1:        @dummy-psu@
 Source2:        @dummy-backlight@
 Source3:        @linux-utils@