sourcepkg: add a complete source package build

[raggi]

If you want to construct a package build for a distribution, you typically need a copy of all of the sources. This produces an archive that has a sufficiently common form that packagers can easily consume.

The final tarball make install target installs .h, .so, .a and .pc into $prefix, e.g.

% find /usr/local -name libtailscale\*
/usr/local/lib/libtailscale.so
/usr/local/lib/libtailscale.a
/usr/local/lib/pkgconfig/libtailscale.pc
/usr/local/include/libtailscale.h

and pkg-config is configured:

% pkg-config --static --cflags libtailscale
-I/usr/local/include
% pkg-config --static --libs libtailscale
-L/usr/local/lib -ltailscale
% pkg-config --libs libtailscale
-L/usr/local/lib -ltailscale

[bradfitz]

Typo package

[crawshaw]

No strong opinions here, something like this makes sense. Is the top-level Makefile necessary or could those targets be in the sourcepkg/Makefile?

[raggi]

I could move the top level makefile, it just gets a bit harder to write (I could also use bash or something to do the work there). The makefile inside sourcepkg is the one that goes in the tar ball, so it could contain the targets but it'd be a bit odd for someone reading it when they just cracked open the tarball.

[crawshaw]

We're going to end up with a lot of bespoke build systems (the Java one is already oof) and so I'm wondering if we can keep ~everything in sub-levels for now. Maybe a Makefile.release that gets renamed int he sourcepkg?

[raggi]

Yeah, makes sense, I'll move it to be contained.

[raggi]

note to self, from crawshaw:

architectures aren't too hard, you can use lipo on a mac to bundle multiple architectures into a single .a

there could be a target in Makefile.src to help users produce this

[raggi]

note to self, from crawshaw:

architectures aren't too hard, you can use lipo on a mac to bundle multiple architectures into a single .a

there could be a target in Makefile.src to help users produce this

I'll have to defer addressing this, as there's something strange going on with the toolchain:

% GOARCH=amd64 GOOS=darwin go build -a -v -x -trimpath -buildmode=c-shared -o libtailscale.dylib.amd64 .
WORK=/var/folders/bb/dyr_1n6j575g8nq85nmnfbt00000gn/T/go-build1117180346
package github.com/tailscale/libtailscale: build constraints exclude all Go files in /Users/raggi/src/github.com/tailscale/libtailscale/sourcepkg/libtailscale
% grep 'build' *.go
%