go: Undefined symbols _macports_legacy_sysconf

[Wowfunhappy (Jonathan)]

Error: Failed to build go: command execution failed

A full copy of the log is attached. However, the relevant section appears to be:

:info:build Undefined symbols for architecture x86_64:
:info:build   "_macports_legacy_sysconf", referenced from:
:info:build       __cgo_a722341dd114_Cfunc_sysconf in _x002.o
:info:build ld: symbol(s) not found for architecture x86_64

Please let me know if you need anything else!

[ryandesign (Ryan Schmidt)]

This particular error is new to me and the occurrence of "macports_legacy" in the undefined symbol name may mean this is a problem with MacPorts legacy support that we can resolve.

However, there have been many other reports of build failures of go on older systems, so the most reliable and future-proof way to get go on macOS is to upgrade to a newer version of macOS.

[kencu (Ken)]

I was trying to figure out where Chris was going with this uncommitted branch <​https://github.com/macports/macports-legacy-support/commit/8f5629a76f9435a2da0d2d7948bfa73107e23376> and perhaps it was for something like this...

[kencu (Ken)]

I am not certain that @ionic ever fully finished his legacysupport tweaks that were designed exactly to get go working on older systems. We did a lot of work in legacysupport for this (some of which I understand :> ) and maybe there is still a bit to do.

[kencu (Ken)]

FWIW -- the bad part of go on older sytems is the C bindings. I actually have a fairly recent go running on 10.6.8 with the C bindings disabled.

<​https://github.com/kencu/SnowLeopardPorts/blob/master/lang/go/Portfile>

a lot of ports that need go to build seem to be OK without the C bindings.

[Wowfunhappy (Jonathan)]

I was trying to see if I could resolve the issue by using an older version of Go.

Go 1.12.1 was explicitly tested and confirmed to work on 10.7. ​https://github.com/macports/macports-ports/commit/f15f259d315c132cce4fb607cfac54ceaceef99d However, for me on 10.9, it fails with the same error as the current version.

I don't know very much about the internals of MacPorts, but this would seem to leave two possibilities: (A) Go 1.12.1 worked on 10.7, but not 10.9, or (B) this is actually a regression in the legacy-support package, which occurred between 0.10_0 (current version at the time of above commit) and 0.12_0 (currently current version).

(I could not figure out how to tell MacPorts to install Go without upgrading legacy-support.)

[kencu (Ken)]

The go port had a bunch of surgery done to it by @ionic to make the legacysupport PG work <​https://github.com/macports/macports-ports/commit/abe46d0764f08fdec9a4923880ce03edbc768a0d>

and then he stripped a lot of it out <​https://github.com/macports/macports-ports/commit/bcfdbd30124a6a6cbfa3fd1afc2da704f6d32b92#diff-5cddd3daff0d75a83514cc9e2aa95e8b> when he said it was incorporated upstream.

That might be why 10.9 is having troubles.

We have a bail-out define to turn off function wrapping for just such eventualities, while this gets sorted out:

<​https://github.com/macports/macports-legacy-support/blob/170f17c6b08ea67532f25e399749ff29e1fbc678/include/MacportsLegacySupport.h#L100>

I'm not that good at go but if you can add this somehow #define __DISABLE_MP_LEGACY_SUPPORT_SYSCONF_WRAP__ you will turn that part of legacysupport off, while Ionic sorts it out.

[ryandesign (Ryan Schmidt)]

Replying to Wowfunhappy:

(I could not figure out how to tell MacPorts to install Go without upgrading legacy-support.)

It should not normally be used, but for testing purposes, you can accomplish this using port's -n switch.

[kencu (Ken)]

Or you could just do a quick edit in the correct legacysupport header to define that

#define __DISABLE_MP_LEGACY_SUPPORT_SYSCONF_WRAP__

build go, and then switch it back if you get really frustrated :>

[erikbs]

Thanks, adding

#define __DISABLE_MP_LEGACY_SUPPORT_SYSCONF_WRAP__ 1

(note the value, 1) immediately after

#define _MACPORTS_LEGACYSUPPORTDEFS_H_

in MacportsLegacySupport.h allowed me to compile go successfully on 10.9.5.

I did, however, encounter some problems with the recommended environment variables, i.e.:

GO_EXTLINK_ENABLED="1"
GO_LDFLAGS="\"-extldflags=-L/opt/local/lib -Wl,-headerpad_max_install_names -lMacportsLegacySupport\""

For some reason go run does not seem to honor them and just spits out the following error:

# command-line-arguments
/opt/local/lib/go/pkg/tool/darwin_amd64/link: running /usr/bin/clang failed: exit status 1
Undefined symbols for architecture x86_64:
  "_fdopendir$INODE64", referenced from:
      _syscall.libc_fdopendir_trampoline in go.o
ld: symbol(s) not found for architecture x86_64
clang: error: linker command failed with exit code 1 (use -v to see invocation)

Passing the values through the -ldflags parameter instead does seem to work, at least with a ​simple test program:

go run -ldflags "-linkmode external -extldflags \"-L/opt/local/lib -Wl,-headerpad_max_install_names -lMacportsLegacySupport\"" hello.go