rustc: Print a smaller hash on -v

The long hash just takes up space and you can discover the main hash through the
`rustc --version verbose` command.

Author: alexcrichton

mk/docs.mk

@@ -112,8 +112,8 @@ HTML_DEPS += doc/version_info.html
 doc/version_info.html: $(D)/version_info.html.template $(MKFILE_DEPS) \
                        $(wildcard $(D)/*.*) | doc/
 	@$(call E, version-info: $@)
-	$(Q)sed -e "s/VERSION/$(CFG_RELEASE)/; s/SHORT_HASH/$(shell echo \
-                    $(CFG_VER_HASH) | head -c 8)/;\
+	$(Q)sed -e "s/VERSION/$(CFG_RELEASE)/; s/SHORT_HASH/$(\
+                    CFG_SHORT_VER_HASH)/;\
                 s/STAMP/$(CFG_VER_HASH)/;" $< >$@
 
 GENERATED += doc/version.tex doc/version_info.html

mk/main.mk

@@ -46,7 +46,8 @@ ifneq ($(wildcard $(subst $(SPACE),\$(SPACE),$(CFG_GIT))),)
 ifneq ($(wildcard $(subst $(SPACE),\$(SPACE),$(CFG_GIT_DIR))),)
     CFG_VER_DATE = $(shell git --git-dir='$(CFG_GIT_DIR)' log -1 --pretty=format:'%ci')
     CFG_VER_HASH = $(shell git --git-dir='$(CFG_GIT_DIR)' rev-parse HEAD)
-    CFG_VERSION += ($(CFG_VER_HASH) $(CFG_VER_DATE))
+    CFG_SHORT_VER_HASH = $(shell git --git-dir='$(CFG_GIT_DIR)' rev-parse --short=9 HEAD)
+    CFG_VERSION += ($(CFG_SHORT_VER_HASH) $(CFG_VER_DATE))
 endif
 endif