as: MD

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1 2.10 Dependency Tracking: '--MD'
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1 'as' can generate a dependency file for the file it creates.  This file
1 consists of a single rule suitable for 'make' describing the
1 dependencies of the main source file.
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1    The rule is written to the file named in its argument.
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1    This feature is used in the automatic updating of makefiles.
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