lib/profile.mk, build-distro: save current commit, when generating a profile

Images building from the generated profile will have mkimage-profiles
commit information.

features.in/build-distro/lib/90-build-distro.mk

@@ -40,8 +40,4 @@ dot-disk:
 	fi
 	@echo "$(ARCH)" >files/.disk/arch
 	@echo "$(DATE)" >files/.disk/date
-	@if type -t git >&/dev/null; then \
-		( cd $(TOPDIR) && test -d .git && \
-		git show-ref --head -ds -- HEAD ||:) \
-		>files/.disk/commit 2>/dev/null; \
-	fi
+	@if [ -s commit ]; then cp commit files/.disk/; fi

lib/profile.mk

@@ -71,6 +71,9 @@ profile/init: distclean
 			[ "$(CHECK)" = 0 ] || exit 1; \
 		fi; \
 	fi; \
+	if type -t git >&/dev/null && [ -d .git ]; then \
+		git show -s --format=%H > "$(BUILDDIR)"/commit; \
+	fi; \
 	mp-commit -i "$(BUILDDIR)" "derivative profile initialized"; \
 	if [ -w . ]; then \
 		rm -f "$(SYMLINK)" && \