make+build: compile SHA1 commit hash into binary

Makefile

@@ -22,7 +22,9 @@ ANDROID_BUILD_DIR := $(MOBILE_BUILD_DIR)/android
 ANDROID_BUILD := $(ANDROID_BUILD_DIR)/Lndmobile.aar
 
 COMMIT := $(shell git describe --abbrev=40 --dirty)
-LDFLAGS := -ldflags "-X $(PKG)/build.Commit=$(COMMIT)"
+COMMIT_HASH := $(shell git rev-parse HEAD)
+LDFLAGS := -ldflags "-X $(PKG)/build.Commit=$(COMMIT) \
+	-X $(PKG)/build.CommitHash=$(COMMIT_HASH)"
 
 BTCD_COMMIT := $(shell cat go.mod | \
 		grep $(BTCD_PKG) | \

build/version.go

@@ -10,9 +10,17 @@ import (
 	"strings"
 )
 
-// Commit stores the current commit hash of this build, this should be set using
-// the -ldflags during compilation.
-var Commit string
+var (
+	// Commit stores the current commit of this build, which includes the
+	// most recent tag, the number of commits since that tag (if non-zero),
+	// the commit hash, and a dirty marker. This should be set using the
+	// -ldflags during compilation.
+	Commit string
+
+	// CommitHash stores the current commit hash of this build, this should
+	// be set using the -ldflags during compilation.
+	CommitHash string
+)
 
 // semanticAlphabet is the set of characters that are permitted for use in an
 // AppPreRelease.