use make implicits for CWEAVE and CTANGLE

PaulBatchelor / voc

A physical model of the human vocal tract using literate programming, based on Pink Trombone.

https://paulbatchelor.github.io/proj/voc

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use make implicits for CWEAVE and CTANGLE #7

Closed belm0 closed 6 years ago

belm0 commented 6 years ago

?= assignment will never have effect on an implicit

PaulBatchelor commented 6 years ago

I don't understand this pull request.

belm0 commented 6 years ago

We used "?=" assignment for CTANGLE, but it will never have effect because CTANGLE is actually a built-in make variable and so always has a value.

There is also a built-in for CWEAVE. So the makefile now uses those (just like $(CC), etc.). If you want to override CTANGLE, you can uncomment the example or do it on the command line.

PaulBatchelor commented 6 years ago

Huh. Didn't realize that. Go figure: https://www.gnu.org/software/make/manual/html_node/Implicit-Variables.html