diff --git a/src/X86_64.ml b/src/X86_64.ml
index 3c8741bcd..dd1a9a66b 100644
--- a/src/X86_64.ml
+++ b/src/X86_64.ml
@@ -560,7 +560,7 @@ let compile_call env ?fname nargs tail =
     in
     let add_argc_counter =
       let argc_before_vararg =
-        Option.map (fun fname -> List.assoc fname vararg_functions) fname
+        Option.bind fname (fun fname -> List.assoc_opt fname vararg_functions)
       in
       match argc_before_vararg with
       (* For vararg functions we add counter of only vararg argumnets.
diff --git a/stdlib/Makefile b/stdlib/Makefile
index 439b39046..3224cff78 100644
--- a/stdlib/Makefile
+++ b/stdlib/Makefile
@@ -2,7 +2,7 @@ SHELL := /bin/bash
 
 FILES=$(wildcard *.lama)
 ALL=$(sort $(FILES:.lama=.o))
-LAMAC=../src/lamac -g
+LAMAC=../src/lamac
 
 all: $(ALL)