Add an .hgignore file (suggested by Mike Williams).

.gitignore

@@ -0,0 +1,39 @@
+# Unixen
+*.o
+src/vim
+src/xxd/xxd
+
+# We do need src/auto/configure and src/auto/config.mk.
+src/auto/osdef.h
+src/auto/config.aap
+src/auto/config.cache
+src/auto/config.h
+src/auto/config.log
+src/auto/config.status
+src/auto/configure.aap
+src/auto/link.log
+src/auto/link.sed
+src/auto/pathdef.c
+
+# Windows
+.hgignore
+*.exe
+*.idb
+*.manifest
+*.exp
+*.obj
+*.pdb
+*.ilk
+*.sln
+*.suo
+*.res
+*.RES
+src/pathdef.c
+gvimext.dll
+gvimext.lib
+
+# All platforms
+*.rej
+*.orig
+*.mo
+*~