Check for db1/ndbm.h and use it in db. Fixes #2647

ext/db/config.m4

@@ -4,6 +4,8 @@ dnl don't forget to call PHP_EXTENSION(db)
 
 divert(1)
 
+AC_CHECK_HEADERS(db1/ndbm.h)
+
 # Checks for libraries.
 # Prefer gdbm, Berkeley DB and ndbm/dbm, in that order
 AC_DEFUN(AC_PREFERRED_DB_LIB,[

ext/db/db.c

@@ -79,8 +79,12 @@
 #define DB_DBM_HSEARCH 1
 #include <db.h>
 #else
+#ifdef HAVE_DB1_NDBM_H
+#include <db1/ndbm.h>
+#else
 #include <ndbm.h>
 #endif
+#endif
 
 #define DBM_TYPE DBM *
 #define DBM_MODE_TYPE int