Fix bug: libpq clients (which include libpq-fe.h) won't compile.

Plus: sigjmp_buf/jmp_buf is backwards, so backend doesn't compile.

src/include/postgres_ext.h

@@ -0,0 +1,39 @@
+/*-------------------------------------------------------------------------
+ *
+ * postgres_ext.h--
+ * 
+ *     This file contains declarations of things that are visible
+ *  external to Postgres.  For example, the Oid type is part of a
+ *  structure that is passed to the front end via libpq, and is
+ *  accordingly referenced in libpq-fe.h.
+ *
+ *     Declarations which are specific to a particular interface should
+ *  go in the header file for that interface (such as libpq-fe.h).  This
+ *  file is only for fundamental Postgres declarations.
+ *
+ *     User-written C functions don't count as "external to Postgres."
+ *  Those function much as local modifications to the backend itself, and 
+ *  use header files that are otherwise internal to Postgres to interface
+ *  with the backend.
+ *
+ * $Id: postgres_ext.h,v 1.1 1996/12/10 07:03:43 bryanh Exp $
+ *
+ *-------------------------------------------------------------------------
+ */
+
+#ifndef POSTGRES_EXT_H
+#define POSTGRES_EXT_H
+
+typedef unsigned int Oid;
+
+/* NAMEDATALEN is the max length for system identifiers (e.g. table names,
+ * attribute names, function names, etc.)
+ *
+ * NOTE that databases with different NAMEDATALEN's cannot interoperate!
+ */ 
+#define NAMEDATALEN 32
+
+/* OIDNAMELEN should be set to NAMEDATALEN + sizeof(Oid) */
+#define OIDNAMELEN  36
+
+#endif