expose new configure variable and update change_tracker

Author: ZuseZ4

Diff for: config.example.toml

@@ -78,6 +78,9 @@
 # Indicates whether the LLVM plugin is enabled or not
 #plugins = false
 
+# Wheter to build Enzyme as AutoDiff backend.
+#enzyme = false
+
 # Indicates whether ccache is used when building LLVM. Set to `true` to use the first `ccache` in
 # PATH, or set an absolute path to use a specific version.
 #ccache = false

Diff for: src/bootstrap/configure.py

@@ -71,6 +71,7 @@ def v(*args):
 # channel, etc.
 o("optimize-llvm", "llvm.optimize", "build optimized LLVM")
 o("llvm-assertions", "llvm.assertions", "build LLVM with assertions")
+o("llvm-enzyme", "llvm.enzyme", "build LLVM with enzyme")
 o("llvm-plugins", "llvm.plugins", "build LLVM with plugin interface")
 o("debug-assertions", "rust.debug-assertions", "build with debugging assertions")
 o("debug-assertions-std", "rust.debug-assertions-std", "build the standard library with debugging assertions")

Diff for: src/bootstrap/src/utils/change_tracker.rs

@@ -225,4 +225,9 @@ pub const CONFIG_CHANGE_HISTORY: &[ChangeInfo] = &[
         severity: ChangeSeverity::Info,
         summary: "New option `llvm.libzstd` to control whether llvm is built with zstd support.",
     },
+    ChangeInfo {
+        change_id: 129176,
+        severity: ChangeSeverity::Info,
+        summary: "New option `llvm.autodiff` to control whether the llvm based autodiff tool (Enzyme) is built.",
+    },
 ];