Issue #21166: fix typo in comment
diff --git a/Makefile.pre.in b/Makefile.pre.in
index c356836..1cfaa05 100644
--- a/Makefile.pre.in
+++ b/Makefile.pre.in
@@ -448,7 +448,7 @@
# pybuilddir.txt contains the name of the build dir and is used for
# sys.path fixup -- see Modules/getpath.c.
# Since this step runs before shared modules are built, try to avoid bootstrap
-# problems by creating a dummy pybuildstr.txt just to allow interpreter
+# problems by creating a dummy pybuilddir.txt just to allow interpreter
# initialization to succeed. It will be overwritten by generate-posix-vars
# or removed in case of failure.
pybuilddir.txt: $(BUILDPYTHON)