Automatic script does not work on Raspbian (Buster)

[rebroad]

$ sudo bash -c "$(wget -O - https://apt.llvm.org/llvm.sh)"
--2024-10-18 10:42:38--  https://apt.llvm.org/llvm.sh
Resolving apt.llvm.org (apt.llvm.org)... 199.232.198.49, 199.232.194.49, 2a04:4e42:4c::561, ...
Connecting to apt.llvm.org (apt.llvm.org)|199.232.198.49|:443... connected.
HTTP request sent, awaiting response... 200 OK
Length: 5811 (5.7K) [application/octet-stream]
Saving to: ‘STDOUT’

-                       100%[============================>]   5.67K  --.-KB/s    in 0.003s

2024-10-18 10:42:38 (1.78 MB/s) - written to stdout [5811/5811]

+ CURRENT_LLVM_STABLE=18
+ BASE_URL=http://apt.llvm.org
+ needed_binaries=(lsb_release wget add-apt-repository gpg)
+ missing_binaries=()
+ for binary in "${needed_binaries[@]}"
+ which lsb_release
+ for binary in "${needed_binaries[@]}"
+ which wget
+ for binary in "${needed_binaries[@]}"
+ which add-apt-repository
+ for binary in "${needed_binaries[@]}"
+ which gpg
+ [[ 0 -gt 0 ]]
+ LLVM_VERSION=18
+ ALL=0
++ lsb_release -is
+ DISTRO=Raspbian
++ lsb_release -sr
+ VERSION=10
+ UBUNTU_CODENAME=
+ CODENAME_FROM_ARGUMENTS=
+ source /etc/os-release
++ PRETTY_NAME='Raspbian GNU/Linux 10 (buster)'
++ NAME='Raspbian GNU/Linux'
++ VERSION_ID=10
++ VERSION='10 (buster)'
++ VERSION_CODENAME=buster
++ ID=raspbian
++ ID_LIKE=debian
++ HOME_URL=http://www.raspbian.org/
++ SUPPORT_URL=http://www.raspbian.org/RaspbianForums
++ BUG_REPORT_URL=http://www.raspbian.org/RaspbianBugs
+ DISTRO=raspbian
+ case ${DISTRO} in
+ [[ -n '' ]]
+ '[' 0 -ge 1 ']'
+ getopts :hm:n: arg
+ [[ 0 -ne 0 ]]
+ declare -A LLVM_VERSION_PATTERNS
+ LLVM_VERSION_PATTERNS[9]=-9
+ LLVM_VERSION_PATTERNS[10]=-10
+ LLVM_VERSION_PATTERNS[11]=-11
+ LLVM_VERSION_PATTERNS[12]=-12
+ LLVM_VERSION_PATTERNS[13]=-13
+ LLVM_VERSION_PATTERNS[14]=-14
+ LLVM_VERSION_PATTERNS[15]=-15
+ LLVM_VERSION_PATTERNS[16]=-16
+ LLVM_VERSION_PATTERNS[17]=-17
+ LLVM_VERSION_PATTERNS[18]=-18
+ LLVM_VERSION_PATTERNS[19]=-19
+ LLVM_VERSION_PATTERNS[20]=
+ '[' '!' _ ']'
+ LLVM_VERSION_STRING=-18
bash: line 140: CODENAME: unbound variable