mozjs91: Parameterize llvm deps (#30336)

Related: chainguard-dev/internal-dev#1545

mozjs91.yaml

@@ -1,29 +1,33 @@
 package:
   name: mozjs91
   version: 91.13.0
-  epoch: 4
+  epoch: 5
   description:
   copyright:
     - license: MPL-2.0
 
+vars:
+  llvm-vers: 18
+
 environment:
   contents:
     packages:
       - build-base
       - busybox
       - ca-certificates-bundle
-      - clang-18
-      - clang-18-dev
+      - clang-${{vars.llvm-vers}}
+      - clang-${{vars.llvm-vers}}-dev
       - curl
       - erlang-dev
       - icu
       - icu-dev
       - jemalloc-dev
-      - llvm-18
-      - llvm-lld-18
+      - llvm-${{vars.llvm-vers}}
+      - llvm-lld-${{vars.llvm-vers}}
       - m4
+      - openssf-compiler-options
       - perl
-      - python-3.10
+      - python-3.10 # Uses imp deprecated in 12 & uses file mode U in 3.11
       - readline-dev
       - rust
       - zlib-dev