gawk: Plugin License

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1 16.2 Extension Licensing
1 ========================
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1 Every dynamic extension must be distributed under a license that is
1 compatible with the GNU GPL (⇒Copying).
1 
1    In order for the extension to tell 'gawk' that it is properly
1 licensed, the extension must define the global symbol
1 'plugin_is_GPL_compatible'.  If this symbol does not exist, 'gawk' emits
1 a fatal error and exits when it tries to load your extension.
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1    The declared type of the symbol should be 'int'.  It does not need to
1 be in any allocated section, though.  The code merely asserts that the
1 symbol exists in the global scope.  Something like this is enough:
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1      int plugin_is_GPL_compatible;
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