Log Message:
devel/samurai: Update to 1.0

Changelog picked from https://github.com/michaelforney/samurai/releases:

New features

* The -d keepdepfile and -d keeprsp debugging options are
  now supported to allow inspection of the generated
  dependency file and RSP file respectively.

Bug fixes

* Failed jobs weren't releasing their pool slot. This could
  cause the build to terminate early when pool depth was 1,
  and the failure limit (-k flag) had not yet been reached.
* Dependency files containing more than one output: input
  line would have the first character of the output path
  skipped on subsequent lines. This would result an error
  since all lines in the dependency file must refer to the
  same output path.
* Empty paths in build edges (e.g. expanded from an undefined
  variable) were not getting rejected, causing a NUL byte to
  be written past the end of the allocation for the path string
  when it was canonicalized as ..
* Recursive rule variable definitions were not detected and
  rejected, causing infinite recursion when attempting to expand them.

Cleanups

* Better error message for dependency log read failure,
  differentiating unexpected EOF from read error.
* Standard output is now line buffered, even when redirected
  to a pipe or regular file. This allows incremental progress
  updates in cases where the output is being saved or piped
  to another command.
* The Makefile now declares dependencies on header files, so
  that during development, objects get rebuilt when the headers change.