diff --git a/nix/bootstrap.nix b/nix/bootstrap.nix
index 1b8b916b10..171aa10105 100644
--- a/nix/bootstrap.nix
+++ b/nix/bootstrap.nix
@@ -1,5 +1,5 @@
 { debug ? false, stage0debug ? false, extraCMakeFlags ? [],
-  stdenv, lib, cmake, gmp, gnumake, bash, buildLeanPackage, writeShellScriptBin, runCommand, symlinkJoin, lndir,
+  stdenv, lib, cmake, gmp, gnumake, bash, buildLeanPackage, writeShellScriptBin, runCommand, symlinkJoin, lndir, perl,
   ... } @ args:
 with builtins;
 rec {
@@ -122,6 +122,7 @@ rec {
       test = buildCMake {
         name = "lean-test-${desc}";
         realSrc = lib.sourceByRegex ../. [ "src.*" "tests.*" ];
+        buildInputs = [ gmp perl ];
         preConfigure = ''
           cd src
         '';
diff --git a/tests/common.sh b/tests/common.sh
index efc8d5e2cb..532ccf9e44 100644
--- a/tests/common.sh
+++ b/tests/common.sh
@@ -27,7 +27,7 @@ function compile_lean {
 
 function exec_capture {
     # mvar suffixes like in `?m.123` are deterministic but prone to change on minor changes, so strip them
-    "$@" 2>&1 | sed -E 's/(\?\w)\.[0-9]+/\1/g' > "$f.produced.out"
+    "$@" 2>&1 | perl -pe 's/(\?\w)\.[0-9]+/\1/g' > "$f.produced.out"
 }
 
 # Remark: `${var+x}` is a parameter expansion which evaluates to nothing if `var` is unset, and substitutes the string `x` otherwise.