Bump llvm to 18

Author: reshke

debian/control

@@ -11,7 +11,7 @@ Rules-Requires-Root: no
 Build-Depends:
  autoconf,
  bison,
- clang-15 [amd64 arm64 mips64el ppc64 ppc64el s390x] <!pkg.postgresql.nollvm>,
+ clang-18 [amd64 arm64 mips64el ppc64 ppc64el s390x] <!pkg.postgresql.nollvm>,
  debhelper-compat (= 13),
  dh-exec (>= 0.13~),
  docbook-xml,
@@ -39,7 +39,7 @@ Build-Depends:
  libxml2-utils,
  libxslt1-dev,
  libzstd-dev (>= 1.4.0) <!pkg.postgresql.nozstd>,
- llvm-15-dev [amd64 arm64 mips64el ppc64 ppc64el s390x] <!pkg.postgresql.nollvm>,
+ llvm-18-dev [amd64 arm64 mips64el ppc64 ppc64el s390x] <!pkg.postgresql.nollvm>,
  lz4 | liblz4-tool,
  mawk,
  openssl,