[gnome-continuous-yocto/gnomeostree-3.28-rocko: 7643/8267] go.bbclass: Enable parallel build

[Emmanuele Bassi <ebassi src gnome org>]

commit 6640f4070e5f3e97e84562a7646e655ee84c0eb5
Author: Otavio Salvador <otavio ossystems com br>
Date:   Fri Sep 8 18:04:37 2017 -0300

    go.bbclass: Enable parallel build
    
    The parallel build is based on PARALLEL_MAKE variable but can be
    overriden setting the GO_PARALLEL_BUILD one.
    
    This change is based on the meta-golang[1] layer. Thanks to Matt
    Madison <matt@madison.systems> for his work on this.
    
    1. https://github.com/madisongh/meta-golang
    
    (From OE-Core rev: 7a40ea8fc358aa134ad86862591329f94d0f3718)
    
    Signed-off-by: Otavio Salvador <otavio ossystems com br>
    Signed-off-by: Richard Purdie <richard purdie linuxfoundation org>

 meta/classes/go.bbclass |   20 ++++++++++++++++++++
 1 files changed, 20 insertions(+), 0 deletions(-)
---
diff --git a/meta/classes/go.bbclass b/meta/classes/go.bbclass
index 720a504..f64b07f 100644
--- a/meta/classes/go.bbclass
+++ b/meta/classes/go.bbclass
@@ -1,11 +1,31 @@
 inherit goarch
 
+def get_go_parallel_make(d):
+    pm = (d.getVar('PARALLEL_MAKE') or '').split()
+    # look for '-j' and throw other options (e.g. '-l') away
+    # because they might have a different meaning in golang
+    while pm:
+        opt = pm.pop(0)
+        if opt == '-j':
+            v = pm.pop(0)
+        elif opt.startswith('-j'):
+            v = opt[2:].strip()
+        else:
+            continue
+
+        return '-p %d' % int(v)
+
+    return ""
+
+GO_PARALLEL_BUILD ?= "${@get_go_parallel_make(d)}"
+
 GOROOT_class-native = "${STAGING_LIBDIR_NATIVE}/go"
 GOROOT = "${STAGING_LIBDIR_NATIVE}/${TARGET_SYS}/go"
 GOBIN_FINAL_class-native = "${GOROOT_FINAL}/bin"
 GOBIN_FINAL = "${GOROOT_FINAL}/${GO_BUILD_BINDIR}"
 
 export GOBUILDFLAGS ?= "-v"
+GOBUILDFLAGS_prepend_task-compile = "${GO_PARALLEL_BUILD} "
 
 export GOOS = "${TARGET_GOOS}"
 export GOARCH = "${TARGET_GOARCH}"