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Georg Sauthoff
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This repository contains the [Illumos][illumos] make source code (in branch
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`illumos`) and based on that a port to Linux (branch `master`).
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The Illumos make is based on Sun's dmake, which is compatible to
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Sun make.
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Motivation: compile old Solaris projects (that use Sun make)
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under Linux without much effort. Think: the C code needs serious
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fixing because it includes metric tons of non-portable constructs
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such that you want to postpone the porting of the existing build
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system (which heavily uses Sun make specific extensions).
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Another motivation to use a Sun compatible make might be the
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inclination to test one of its extensions, e.g. target groups,
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command and hidden dependencies.
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2016, Georg Sauthofff <mail@georg.so>
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## Background
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Illumos is based on [OpenSolaris][osolaris], the now discontinued
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open-source version of Solaris. OpenSolaris was started by Sun
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after the Solaris 10 release and was closed down in 2010 after
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Oracle bought Sun. Sun used the [CDDL][cddl] license on its open
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sourced code.
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Traditionally, Solaris includes it own version of `make` under
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`/usr/ccs/bin/make`, also known as 'Sun make'. It has some
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extensions over other make versions, such as BSD make and
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[POSIX][posix] make. It only supports sequential execution
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(unlike e.g. GNU make), however, Sun also developed `dmake`
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(think: distributed make), usually bundled with the [Solaris
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compiler suite 'Solaris Studio'][solstudio]. Dmake is compatible
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with the Sun make syntax and besides serial execution it supports
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parallel execution on an SMP system and on a cluster (apparently
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similar to [distcc][distcc]). It was also open-sourced by Sun
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under the CDDL.
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Illumos started with the code base that included the original Sun
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make but later switched to dmake.
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## Related make Implementations
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[GNU make][gmake] is the most popular, portable and thus relevant
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make. Similar to most GNU tools it contains many very useful
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extension over the traditional make and it basically runs
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everywhere.
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Examples of GNU make features that are missing from Sun make:
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- parallel execution (the Sun make compatible dmake supports it)
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- conditional constructs
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- many built-in function
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- user-defined functions
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- templates
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- guile integration
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- generation of included files
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Sun make features that aren't supported by GNU make:
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- target groups - i.e. to specify that more than one target
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depends on a source file and that the one action generates
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those targets at once. GNU make only supports a group of
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targets with pattern rules.
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- command dependencies - i.e. a target is also considered
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out-of-date if the command changes - i.e. due to changed values
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of variables like `$(CC)` or `$(CFLAGS)`
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- hidden dependencies - automatic discovery of header
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dependencies
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There are also extension where GNU and Sun make just use
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different syntax. For example, conditional macros:
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- Sun make: `target := VAR = value`
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- GNU make: `taget: VAR = value`
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(Note that GNU make interprets `:=` as assignment with immediate
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expansion.)
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The distributed make that came with OpenOffice is [also named
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DMake][oodmake]. It seems that it was independently developed of Sun's
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dmake - and that it uses a different syntax.
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## Portability
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The changes in the `master` branch fix portability issues in the
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original code such that the resulting `make` compiles and runs
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under Linux. Also, a [CMake][cmake] build file is included for portable
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building.
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Although those changes target Linux, they aren't really Linux
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specific. That means that the ported make should also compile on
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other modern [POSIXy][posix] operating systems.
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## Naming
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I avoided the names `dmake`, `imake` and `smake` because there
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are already multiple published make versions that use those
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names. There is a [dmake][dmake] that comes with Solaris Studio, a [dmake
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bundled with OpenOffice][oodmake], a dmake that OpenOffice's
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dmake is based on, an [imake][imake] to build old X versions and
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the [Schily smake][smake].
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Thus, to not add to the confusion I chose `somake`.
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## License
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Perhaps not required by the CDDL, but I license my changes
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also under the [CDDL][cddl].
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[illumos]: https://en.wikipedia.org/wiki/Illumos
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[osolaris]: https://en.wikipedia.org/wiki/OpenSolaris
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[solaris]: https://en.wikipedia.org/wiki/Solaris_(operating_system)
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[cddl]: https://en.wikipedia.org/wiki/Common_Development_and_Distribution_License
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[distcc]: https://en.wikipedia.org/wiki/Distcc
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[solstudio]: https://en.wikipedia.org/wiki/Oracle_Developer_Studio
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[gmake]: https://www.gnu.org/software/make/
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[oodmake]: https://www.openoffice.org/tools/dmake/
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[cmake]: https://en.wikipedia.org/wiki/CMake
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[posix]: https://en.wikipedia.org/wiki/POSIX#Mostly_POSIX-compliant
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[smake]: https://sourceforge.net/projects/s-make/
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[imake]: https://en.wikipedia.org/wiki/Imake
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[dmake]: https://docs.oracle.com/cd/E24457_01/html/E25220/index.html
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