diff --git a/bin/dune b/bin/dune
index c7e714a..1b7a3d0 100644
--- a/bin/dune
+++ b/bin/dune
@@ -3,5 +3,6 @@
  (name main)
  (modules main)
  (libraries gtirb_semantics base64 yojson asli.libASL llvm_disas)
+ (flags     :standard -cclib (:include ../llvm-disas/llvmconf.sexp))
 )
 
diff --git a/llvm-disas/dune b/llvm-disas/dune
index 2e423d7..99fff35 100644
--- a/llvm-disas/dune
+++ b/llvm-disas/dune
@@ -8,6 +8,7 @@
 
 (rule 
  (targets llvmconf.sexp)
- (action (bash "$(opam var conf-llvm:config) --libs > llvmconf.sexp"))
+ ; use opam if present otherwise fall back to $LLVM_CONFIG
+ (action (bash "if command -v opam; then llvm_config=$(opam var conf-llvm:config); fi ; ${llvm_config:-$LLVM_CONFIG} --libs > llvmconf.sexp"))
 )