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) | \