bu_dehumanize_number is derived from NetBSD's implementation:
NetBSD: dehumanize_number.c,v 1.4 2012/03/13

Copyright (c) 2005, 2006 The NetBSD Foundation, Inc.
All rights reserved.

This code is derived from software contributed to The NetBSD Foundation
by Julio M. Merino Vidal, developed as part of Google's Summer of Code
2005 program.

Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions
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   notice, this list of conditions and the following disclaimer.
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   documentation and/or other materials provided with the distribution.

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file:/src/libbu/units_dehumanize.c
