BUG #13898: ecpg complains on nested comments in /usr/pgsql-9.4/include/informix/esql/datetime.h

The following bug has been logged on the website:

Bug reference: 13898
Logged by: vladimir zvagolskiy
Email address: vladimir(dot)zvagolskiy(at)nasdaq(dot)com
PostgreSQL version: 9.4.5
Operating system: Centos 7.1
Description:

Hi guys,

We experience a ecpg build issue for INFORMIX dialect:

[vlzv(at)inetlinux10 ecpg_9.4_issue]$ cat simple.ec
EXEC SQL include datetime;

[vlzv(at)inetlinux10 ecpg_9.4_issue]$ /usr/pgsql-9.4/bin/ecpg -C INFORMIX -I
/usr/pgsql-9.4/include/informix/esql simple.ec
/usr/pgsql-9.4/include/informix/esql/datetime.h:9: ERROR: nested /* ... */
comments

[vlzv(at)inetlinux10 ecpg_9.4_issue]$ rpm -qf
/usr/pgsql-9.4/include/informix/esql/datetime.h
postgresql94-devel-9.4.5-1PGDG.rhel7.x86_64

once I modify datetime.h file as per below diff, the issue disappears.
[vlzv(at)inetlinux10 ecpg_9.4_issue]$ cat -n
/usr/pgsql-9.4/include/informix/esql/datetime.h
1 /* src/interfaces/ecpg/include/datetime.h */
2
3 #ifndef _ECPG_DATETIME_H
4 #define _ECPG_DATETIME_H
5
6 #include <ecpg_informix.h>
7
8 #ifndef _ECPGLIB_H /* source created by
ecpg which defines thes
9 /*
symbols */
10 typedef timestamp dtime_t;
11 typedef interval intrvl_t;
12 #endif /* ndef _ECPGLIB_H */
13
14 #endif /* ndef _ECPG_DATETIME_H */

[vlzv(at)inetlinux10 ecpg_9.4_issue]$ diff
/usr/pgsql-9.4/include/informix/esql/datetime.h
/usr/pgsql-9.4/include/informix/esql/datetime.h.orig
9c9
< /* symbols
*/
---
> * symbols
*/

[vlzv(at)inetlinux10 ecpg_9.4_issue]$ /usr/pgsql-9.4/bin/ecpg -C INFORMIX -I
/usr/pgsql-9.4/include/informix/esql simple.ec
[vlzv(at)inetlinux10 ecpg_9.4_issue]$ ls -l ./simple.c
-rw-rw-r-- 1 vlzv vlzv 700 Jan 29 11:15 ./simple.c