[Buildroot] [[PATCH v2 1/2] package/pkg-golang: add support for building host packages

[Mirza Krak]

With this you can add:

    $(eval $(host-golang-package))

to a package .mk file to build for host.

Signed-off-by: Mirza Krak <mirza.krak at northern.tech>
---

Changes in v2:
    - Added entry in Buildroot manual
    - Install to $(HOST_DIR)/bin instead of $(HOST_DIR)/usr/bin
    - Created "GO_COMMON_ENV" to be shared between GO_TARGET_ENV and GO_HOST_ENV
    - Dropped accidental change of comment
    - Removed a empty line

 docs/manual/adding-packages-golang.txt |  5 +++--
 package/pkg-golang.mk                  | 37 +++++++++++++++++++++++++++++++---
 2 files changed, 37 insertions(+), 5 deletions(-)

diff --git a/docs/manual/adding-packages-golang.txt b/docs/manual/adding-packages-golang.txt
index efcf696867..94520480ce 100644
--- a/docs/manual/adding-packages-golang.txt
+++ b/docs/manual/adding-packages-golang.txt
@@ -50,8 +50,9 @@ and +BR2_PACKAGE_HOST_GO_CGO_LINKING_SUPPORTS+ because Buildroot will
 automatically add a dependency on +host-go+ to such packages.

 The main macro of the Go package infrastructure is
-+golang-package+. It is similar to the +generic-package+ macro. Only
-target packages are supported with +golang-package+.
++golang-package+. It is similar to the +generic-package+ macro. The
+ability to build host packages is also available, with the
++host-golang-package+ macro.

 Just like the generic infrastructure, the Go infrastructure works
 by defining a number of variables before calling the +golang-package+.
diff --git a/package/pkg-golang.mk b/package/pkg-golang.mk
index 6eacd14180..878228ce74 100644
--- a/package/pkg-golang.mk
+++ b/package/pkg-golang.mk
@@ -25,12 +25,18 @@ GO_BIN = $(HOST_DIR)/bin/go

 # We pass an empty GOBIN, otherwise "go install: cannot install
 # cross-compiled binaries when GOBIN is set"
-GO_TARGET_ENV = \
-	$(HOST_GO_TARGET_ENV) \
+GO_COMMON_ENV = \
 	PATH=$(BR_PATH) \
 	GOBIN= \
 	CGO_ENABLED=$(HOST_GO_CGO_ENABLED)

+GO_TARGET_ENV = \
+	$(HOST_GO_TARGET_ENV) \
+	$(GO_COMMON_ENV)
+
+GO_HOST_ENV = \
+	$(GO_COMMON_ENV)
+
 ################################################################################
 # inner-golang-package -- defines how the configuration, compilation and
 # installation of a Go package should be done, implements a few hooks to tune
@@ -44,7 +50,6 @@ GO_TARGET_ENV = \
 #             packages
 #  argument 4 is the type (target or host)
 #
-# NOTE Only type target is supported at the moment
 ################################################################################

 define inner-golang-package
@@ -96,6 +101,8 @@ endif
 # Build step. Only define it if not already defined by the package .mk
 # file.
 ifndef $(2)_BUILD_CMDS
+ifeq ($(4),target)
+# Build package for target
 define $(2)_BUILD_CMDS
 	$$(foreach d,$$($(2)_BUILD_TARGETS),\
 		cd $$($(2)_SRC_PATH); \
@@ -107,6 +114,20 @@ define $(2)_BUILD_CMDS
 			./$$(d)
 	)
 endef
+else
+# Build package for host
+define $(2)_BUILD_CMDS
+	$$(foreach d,$$($(2)_BUILD_TARGETS),\
+		cd $$($(2)_SRC_PATH); \
+		$$(GO_HOST_ENV) \
+			GOPATH="$$(@D)/$$($(2)_WORKSPACE)" \
+			$$($(2)_GO_ENV) \
+			$$(GO_BIN) build -v $$($(2)_BUILD_OPTS) \
+			-o $$(@D)/bin/$$(or $$($(2)_BIN_NAME),$$(notdir $$(d))) \
+			./$$(d)
+	)
+endef
+endif
 endif

 # Target installation step. Only define it if not already defined by the
@@ -119,6 +140,15 @@ define $(2)_INSTALL_TARGET_CMDS
 endef
 endif

+# Host installation step
+ifndef $(2)_INSTALL_CMDS
+define $(2)_INSTALL_CMDS
+	$$(foreach d,$$($(2)_INSTALL_BINS),\
+		$(INSTALL) -D -m 0755 $$(@D)/bin/$$(d) $(HOST_DIR)/bin/$$(d)
+	)
+endef
+endif
+
 # Call the generic package infrastructure to generate the necessary make
 # targets
 $(call inner-generic-package,$(1),$(2),$(3),$(4))
@@ -130,3 +160,4 @@ endef # inner-golang-package
 ################################################################################

 golang-package = $(call inner-golang-package,$(pkgname),$(call UPPERCASE,$(pkgname)),$(call UPPERCASE,$(pkgname)),target)
+host-golang-package = $(call inner-golang-package,host-$(pkgname),$(call UPPERCASE,host-$(pkgname)),$(call UPPERCASE,$(pkgname)),host)
--
2.11.0