Add new port: devel/mage

Mage is a make/rake-like build tool using Go. You write plain-old go functions,
and Mage automatically uses them as Makefile-like runnable targets.
Makefiles are hard to read and hard to write. Mostly because makefiles are
essentially fancy bash scripts with significant white space and additional
make-related syntax.

Approved by:	swills (mentor)
Differential Revision:	https://reviews.freebsd.org/D15159

devel/Makefile

@@ -1699,6 +1699,7 @@
     SUBDIR += m17n-docs
     SUBDIR += m17n-lib
     SUBDIR += m4
+    SUBDIR += mage
     SUBDIR += magit
     SUBDIR += magit-popup
     SUBDIR += make++

devel/mage/Makefile

@@ -0,0 +1,38 @@
+# $FreeBSD$
+
+PORTNAME=	mage
+DISTVERSIONPREFIX=	v
+DISTVERSION=	2.1.0
+CATEGORIES=	devel
+
+MAINTAINER=	seanc@FreeBSD.org
+COMMENT=	Command-line make-like build tool using Go as input files
+
+LICENSE=	APACHE20
+LICENSE_FILE=	${WRKSRC}/LICENSE
+
+BUILD_DEPENDS=	go:lang/go
+
+USE_GITHUB=	yes
+GH_ACCOUNT=	magefile
+GH_SUBDIR=	src/github.com/${GH_ACCOUNT}/${PORTNAME}
+GH_TAGNAME=	2.1
+GH_TAG_COMMIT=	771ebed
+
+PLIST_FILES=	bin/mage
+
+pre-patch:
+	@${SED} -e "s|%%GH_TAGNAME%%|${GH_TAGNAME}|g; s|%%GH_TAG_COMMIT%%|${GH_TAG_COMMIT}|g" \
+		${FILESDIR}/patch-magefile.go > ${WRKSRC}/magefile.go.patch
+
+do-patch:
+	@cd ${WRKSRC} && ${PATCH} --forward --quiet -p2 < magefile.go.patch
+
+do-build:
+	@cd ${WRKSRC} && ${SETENV} ${MAKE_ENV} CGO_ENABLED=0 GOPATH=${WRKSRC} \
+	${LOCALBASE}/bin/go run bootstrap.go
+
+do-install:
+	${INSTALL_PROGRAM} ${WRKSRC}/bin/${PORTNAME} ${STAGEDIR}${PREFIX}/bin/${PORTNAME}
+
+.include <bsd.port.mk>

devel/mage/distinfo

@@ -0,0 +1,3 @@
+TIMESTAMP = 1524434645
+SHA256 (magefile-mage-v2.1.0-2.1_GH0.tar.gz) = ac4ad1cfaf0a4ee67b1cbb0ea52792c5bc2ce240ee763fdc8d537bb14b40011a
+SIZE (magefile-mage-v2.1.0-2.1_GH0.tar.gz) = 8777256

devel/mage/files/patch-magefile.go

@@ -0,0 +1,17 @@
+--- magefile.go.orig	2018-04-11 17:03:07 UTC
++++ magefile.go
+@@ -83,12 +83,14 @@ func flags() (string, error) {
+ 
+ // tag returns the git tag for the current branch or "" if none.
+ func tag() string {
++	return "%%GH_TAGNAME%%"
+ 	s, _ := sh.Output("git", "describe", "--tags")
+ 	return s
+ }
+ 
+ // hash returns the git hash for the current repo or "" if none.
+ func hash() string {
++	return "%%GH_TAG_COMMIT%%"
+ 	hash, _ := sh.Output("git", "rev-parse", "--short", "HEAD")
+ 	return hash
+ }

devel/mage/pkg-descr

@@ -0,0 +1,17 @@
+Mage is a make/rake-like build tool using Go. You write plain-old go functions,
+and Mage automatically uses them as Makefile-like runnable targets.
+
+Makefiles are hard to read and hard to write. Mostly because makefiles are
+essentially fancy bash scripts with significant white space and additional
+make-related syntax.
+
+Mage lets you have multiple magefiles, name your magefiles whatever you want,
+and they're easy to customize for multiple operating systems. Mage has no
+dependencies (aside from go) and runs just fine on all major operating systems,
+whereas make generally uses bash which is not well supported on Windows. Go is
+superior to bash for any non-trivial task involving branching, looping, anything
+that's not just straight line execution of commands. And if your project is
+written in Go, why introduce another language as idiosyncratic as bash? Why not
+use the language your contributors are already comfortable with?
+
+WWW: https://magefile.org/