A Patch for MIC to EUC_TW code converting in mb support

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POSTGRESQL BUG REPORT: MIC to EUC_TW code converting in mb support
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System Configuration
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Architecture (example: Intel Pentium) :x86
Operating System (example: Linux 2.0.26 ELF) :Linux 2.2.x and FreeBSD
3.5R
PostgreSQL version (example: PostgreSQL-7.0) :PostgreSQL-7.0.2
Compiler used (example: gcc 2.8.0) :egcs-2.91.66, gcc 2.7.3

A FULL description of the problem:
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In PostgreSQL mb (multi-byte) support, there is a bug in code converting

for MIC to EUC_TW. Original mic2euc_tw() in conv.c converts CNS
11643-1992
Plane 2 into 2 bytes EUC_TW encoding. But characters in CNS 11643-1992
Plane 2
should be converted into 4 bytes EUC_TW encoding instead.

A way to repeat the problem:
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When you initdb with -E EUC_TW and set PGCLIENTENCODING to BIG5,
you will find all the characters in CNS 11643-1992 Plane 2 are
incorrectly stored or output.

This problem might be fixed by the solution in the attachement.