cmd/go: "#cgo pkg-config:" comments do not work with gccgo

[Matthias Klose]

see https://github.com/golang/go/issues/11739

recipe for work around: https://github.com/lxc/go-lxc/issues/33

[Matthias Klose (doko)]

as long as this is not yet implemented, you can work around this by:

DEB_HOST_ARCH ?= $(shell dpkg-architecture -qDEB_HOST_ARCH)

ifneq (,$(filter $(DEB_HOST_ARCH), powerpc s390x))
  pkg_configs = dbus-1 libnih libnih-dbus glib-2.0 gobject-2.0 ... and more
  export CGO_CFLAGS := \
    $(shell $(foreach pkg, $(pkg_configs), pkg-config --cflags $(pkg); ))
  export CGO_CXXFLAGS := $(CGO_CFLAGS)
  export CGO_LDFLAGS := \
    $(shell $(foreach pkg, $(pkg_configs), pkg-config --libs $(pkg); ))
  $(warning setting CGO_CFLAGS = $(CGO_CFLAGS))
  $(warning setting CGO_CXXFLAGS = $(CGO_CXXFLAGS))
  $(warning setting CGO_LDFLAGS = $(CGO_LDFLAGS))
endif

[Michael Hudson-Doyle (mwhudson)]

I've proposed a fix at https://go-review.googlesource.com/18790. Assuming Ian doesn't hate the sight of it, it would be good to chuck it in as a distro patch for gccgo 5 and test it out on some of those packages that don't build with gccgo.

[Michael Hudson-Doyle (mwhudson)]

Actual patch: http://paste.ubuntu.com/14587239/

[Matthias Klose (doko)]

ftbfs in GCC trunk

../../src/gotools/../libgo/go/cmd/go/build.go:2563:7: error: reference to undefined name 'err'
if err != nil {
^

Makefile:671: recipe for target 'go' failed
make[4]: *** [go] Error 1
make[4]: Leaving directory '/scratch/packages/gcc/6/gcc-6-6-20160122/build/gotools'
Makefile:12918: recipe for target 'all-gotools' failed
make[3]: *** [all-gotools] Error 2

[Michael Hudson-Doyle (mwhudson)]

Sorry about that. Try this one instead http://paste.ubuntu.com/14691833/

[Michael Hudson-Doyle (mwhudson)]

Argh even that one isn't quite right.

Patch for gcc 5: //paste.ubuntu.com/14692803/ (built and tested)
Patch for gcc master: //paste.ubuntu.com/14692814/ (not built in a gcc tree, but it's the same patch as //paste.ubuntu.com/14692814/ which I have tested)

[Michael Hudson-Doyle (mwhudson)]

Er let's try that again.

Patch for gcc 5: http://paste.ubuntu.com/14692803
Patch for gcc master: http://paste.ubuntu.com/14692814 (which is the same patch as https://go-review.googlesource.com/#/c/18790/4)

[Michael Hudson-Doyle (mwhudson)]

Third time's a charm. *this* is the patch for gcc master: http://paste.ubuntu.com/14692846/

[Matthias Klose (doko)]

fixed for xenial