[Minor] Add missing definitions

config.h.in

@@ -51,6 +51,7 @@
 #cmakedefine HAVE_MACHINE_ENDIAN_H  1
 #cmakedefine HAVE_MATH_H         1
 #cmakedefine HAVE_MAXPATHLEN     1
+#cmakedefine HAVE_FMEMOPEN       1
 #cmakedefine HAVE_MEMSET_S       1
 #cmakedefine HAVE_MKSTEMP        1
 #cmakedefine HAVE_MMAP_ANON      1
@@ -62,8 +63,9 @@
 #cmakedefine HAVE_NETINET_TCP_H  1
 #cmakedefine HAVE_NFTW           1
 #cmakedefine HAVE_OASYNC         1
-#cmakedefine HAVE_ONOFOLLOW      1
 #cmakedefine HAVE_OCLOEXEC       1
+#cmakedefine HAVE_ONOFOLLOW      1
+#cmakedefine HAVE_OPENMEMSTREAM  1
 #cmakedefine HAVE_OPENSSL        1
 #cmakedefine HAVE_O_DIRECT       1
 #cmakedefine HAVE_PATH_MAX       1