[libc++] Add the version header to all headers.
Some headers which require the version header depend on other headers to
provide it. Include the version header in all top-level headers to make
sure a header cleanup can't remove the version header.
Note this doesn't add the version header to the c headers.
Reviewed By: #libc, Quuxplusone, ldionne
Differential Revision: https://reviews.llvm.org/D116172
NOKEYCHECK=True
GitOrigin-RevId: bd6e6846e7f431e9d84b1f257d4a0c8ddeac4fe2
diff --git a/include/sstream b/include/sstream
index e63d143..6ad624a 100644
--- a/include/sstream
+++ b/include/sstream
@@ -184,6 +184,7 @@
#include <istream>
#include <ostream>
#include <string>
+#include <version>
#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
#pragma GCC system_header