psql front-end tool, unsetenv failed in solaris

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Your name : Ki-hyun Yoon
Your email address : abird(at)seedvr(dot)com

System Configuration
---------------------
Architecture (example: Intel Pentium) : Intel Pentium

Operating System (example: Linux 2.0.26 ELF) : Solaris x86 2.7

PostgreSQL version (example: PostgreSQL-6.4.2) : PostgreSQL-6.4.2

Compiler used (example: gcc 2.8.0) : gcc 2.8.1

Please enter a FULL description of your problem:
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There is no unsetenv function in solaris environment.
So, I failed in compiling psql front-end tool.
Umm, I first compiled postgresql with no with-mb option.
Next I reconfigured it with with-mb option.
This only can exist in MULTI-BYTE environment.

I changed that line.
! unsetenv("PGCLIENT...");
! putenv("PGCLIENT...=");

This is very simple port-problem.
Thanks.