[perl #36770] [PATCH] build_tools/ops2c.pl - Improve command line processing

[Tom @ Nekomimists . Ddo . Jp]

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This patch changes build_tools/ops2c.pl

1. to use Pod::Usage. perldoc comment becomes usage.
2. to check parameters strictly. A routine to check if trans parameter
is one of (C | CGoto | CGP | CSwitch | CPrederef) is added.