diff --git a/bootstrap.sh b/bootstrap.sh
index fa50737..9f43ff3 100755
--- a/bootstrap.sh
+++ b/bootstrap.sh
@@ -3,7 +3,7 @@
 test -n "${EXTRA_PKGS}" && apk add --no-cache ${EXTRA_PKGS}
 test -n "${EXTRA_GEMS}" && gem install --no-user-install --no-document ${EXTRA_GEMS}
 
-su-exec builder /usr/local/bin/gem-compiler
+su-exec builder GEM_COMPILER_FLAGS="${GEM_COMPILER_FLAGS}" /usr/local/bin/gem-compiler
 
 exit_status=$?