+# See comments in build-aux/git-version-gen. However, we make .version depend
+# on configure so that .version and VERSION/PACKAGE_VERSION stay in sync in the
+# working copy (for example, when you run autoreconf && make). Allowing these
+# to fall out of sync appears to have little potential to improve Bison build
+# efficiency (even if we were to replace VERSION/PACKAGE_VERSION with .version
+# everywhere possible). On the other hand, it could be harmful. For example,
+# a developer might naively reference .version in a test case while the bison
+# executable still compiles with VERSION, and so the test case might fail or
+# pass incorrectly.
+BUILT_SOURCES += $(top_srcdir)/.version
+$(top_srcdir)/.version: configure