migrate to top level vcsinfo support

lib/vcsinfo.zsh

@@ -0,0 +1,25 @@
+# Use the following within your prompt
+#   ${vcs_info_msg_0_}
+#
+# The style of vcs_info can be tweaked within a theme by modifying the output
+# using zstyle.
+#
+# http://zsh.sourceforge.net/Doc/Release/User-Contributions.html#IDX2133
+#
+
+typeset -ga precmd_functions
+autoload -Uz vcs_info
+
+zstyle ':vcs_info:git:*' check-for-changes true
+zstyle ':vcs_info:git:*' formats "$ZSH_THEME_GIT_PROMPT_PREFIX%b%u%F$ZSH_THEME_GIT_PROMPT_SUFFIX"
+zstyle ':vcs_info:git:*' unstagedstr "$ZSH_THEME_GIT_PROMPT_DIRTY"
+
+zsh_vcsinfo_precmd() {
+  vcs_info
+}
+
+vcs_prompt_info() {
+  echo "${vcs_info_msg_0_}"
+}
+
+precmd_functions+='zsh_vcsinfo_precmd'