diff --git a/src/Leanc.lean b/src/Leanc.lean
index 34469aba41..bd5099f024 100644
--- a/src/Leanc.lean
+++ b/src/Leanc.lean
@@ -21,10 +21,10 @@ Beware of the licensing consequences since GMP is LGPL."
 
   -- We assume that the CMake variables do not contain escaped spaces
   let cflags := ["-I", (root / "include").toString] ++ "@LEANC_EXTRA_FLAGS@".trim.splitOn
-  let cflagsHidden := "@LEANC_INTERNAL_FLAGS@".trim.splitOn
+  let mut cflagsInternal := "@LEANC_INTERNAL_FLAGS@".trim.splitOn
   let mut ldflags := ["-L", (root / "lib").toString, "-L", (root / "lib" / "lean").toString, (← IO.getEnv "LEANC_GMP").getD "-lgmp"] ++ "@LEAN_EXTRA_LINKER_FLAGS@".trim.splitOn
   let mut ldflagsExt := "@LEANC_STATIC_LINKER_FLAGS@".trim.splitOn
-  let ldflagsHidden := "@LEANC_INTERNAL_LINKER_FLAGS@".trim.splitOn
+  let mut ldflagsInternal := "@LEANC_INTERNAL_LINKER_FLAGS@".trim.splitOn
 
   for arg in args do
     match arg with
@@ -42,8 +42,14 @@ Beware of the licensing consequences since GMP is LGPL."
       return 0
     | _ => ()
 
-  let cc := rootify <| (← IO.getEnv "LEAN_CC").getD "@LEANC_CC@"
-  let args := cflags ++ cflagsHidden ++ args ++ ldflagsExt ++ ldflags ++ ldflagsHidden ++ ["-Wno-unused-command-line-argument"]
+  let mut cc := "@LEANC_CC@"
+  if let some cc' ← IO.getEnv "LEAN_CC" then
+    cc := cc'
+    -- these are intended for the bundled compiler only
+    cflagsInternal := []
+    ldflagsInternal := []
+  cc := rootify cc
+  let args := cflags ++ cflagsInternal ++ args ++ ldflagsExt ++ ldflags ++ ldflagsInternal ++ ["-Wno-unused-command-line-argument"]
   let args := args.map rootify
   if args.contains "-v" then
     IO.eprintln s!"{cc} {" ".intercalate args}"