rename git.mk to gitver.mk

This is a more descriptive name since this file only sets the gitver
variable.

Makefile

@@ -22,7 +22,7 @@ include ${MK}/sys.mk
 include ${MK}/os.mk
 include ${MK}/subdir.mk
 include ${MK}/dist.mk
-include ${MK}/git.mk
+include ${MK}/gitver.mk
 
 _installafter:
 ifeq (${MKPREFIX},yes)

src/rc/Makefile

@@ -42,7 +42,7 @@ LDADD+=		-lutil -lrc -leinfo
 include ../../Makefile.inc
 MK=		../../mk
 include ${MK}/prog.mk
-include ${MK}/git.mk
+include ${MK}/gitver.mk
 include ${MK}/cc.mk
 
 include ${MK}/termcap.mk