Having a non-standard (different than 1) patch level requirement means the
patches cannot be composed easily from different origins. The following
command was used to remove one level from the llvm-9 patches:
sed -e 's|^--- a/|--- |' -e 's|^+++ b/|+++ |' \
gnu/packages/patches/llvm-9* -i
* gnu/packages/llvm.scm (llvm-9)[source]: Drop the patch-flags field.
Re-indent list of patches.
* gnu/packages/patches/llvm-9-fix-bitcast-miscompilation.patch: Strip one level.
* gnu/packages/patches/llvm-9-fix-lpad-miscompilation.patch: Likewise.
* gnu/packages/patches/llvm-9-fix-scev-miscompilation.patch: Likewise.
