+ added initial SCM root detection for OMZ SCM plugin

lib/scm.zsh

@@ -0,0 +1,29 @@
+SCM_DEBUG=yes # comment line to disable debugging
+_scm_types=(git hg svn) && export _scm_types
+
+function _scm_debug { [ $SCM_DEBUG ] && echo $* >&2 }
+
+# Checks given 1st path argument if it's root of .git|.hg|.svn 
+function _scm_get_scm_type {
+  for type ($_scm_types) {
+    [ ! -d "$1/.$type" ] && continue
+
+    _scm_debug "   -> Is a $type repository"
+    export SCM_ROOT=$1
+    export SCM_TYPE=$type
+    return 0
+  }
+  
+  return 1
+} 
+
+# Recursive lookup for possible SCM root from current dir => /
+function scm_detect_root {
+  [[ $# -eq 1 && "$1" = "" ]] && return # touched the root (/)
+  _DETECT_WD=${1:-$PWD}
+  
+  _scm_debug -ne "."
+
+  _scm_get_scm_type "$_DETECT_WD" && return
+  scm_detect_root "${_DETECT_WD%/*}"
+}