add CPython development versions (2.[67]-dev, 3.[1234]-dev)

plugins/python-build/bin/pyenv-install

@@ -148,8 +148,13 @@ if [ -z "${PYTHON_BUILD_CACHE_PATH}" ] && [ -d "${PYENV_ROOT}/cache" ]; then
   export PYTHON_BUILD_CACHE_PATH="${PYENV_ROOT}/cache"
 fi
 
-# Default PYENV_VERSION to the globally-specified Python version.
-export PYENV_VERSION="$(pyenv global 2>/dev/null || true)"
+# Default PYENV_VERSION to the globally-specified Python version. (The
+# Python 3.4 installer requires an existing Python installation to run. An
+# unsatisfied local .python-version file can cause the installer to
+# fail.)
+if [ -z "${PYENV_VERSION}" ]; then
+  export PYENV_VERSION="$(pyenv global 2>/dev/null || true)"
+fi
 
 
 # Execute `before_install` hooks.

plugins/python-build/bin/python-build

@@ -104,6 +104,10 @@ install_git() {
   install_package_using "git" 2 "$@"
 }
 
+install_hg() {
+  install_package_using "hg" 2 "$@"
+}
+
 install_svn() {
   install_package_using "svn" 2 "$@"
 }
@@ -355,6 +359,38 @@ fetch_git() {
   fi
 }
 
+fetch_hg() {
+  local package_name="$1"
+  local hg_url="$2"
+  local hg_ref="$3"
+
+  echo "Cloning ${hg_url}..." >&2
+
+  if type hg &>/dev/null; then
+    if [ -n "$PYTHON_BUILD_CACHE_PATH" ]; then
+      pushd "$PYTHON_BUILD_CACHE_PATH" >&4
+      local clone_name="$(sanitize "$hg_url")"
+      if [ -e "${clone_name}" ]; then
+        { cd "${clone_name}"
+          hg pull --force "$hg_url"
+        } >&4 2>&1
+      else
+        { hg clone --branch "$hg_ref" "$hg_url" "${clone_name}"
+          cd "${clone_name}"
+          hg update null
+        } >&4 2>&1
+      fi
+      hg_url="$PYTHON_BUILD_CACHE_PATH/${clone_name}"
+      popd >&4
+    fi
+
+    hg clone --branch "$hg_ref" "$hg_url" "${package_name}" >&4 2>&1
+  else
+    echo "error: please install \`hg\` and try again" >&2
+    exit 1
+  fi
+}
+
 fetch_svn() {
   local package_name="$1"
   local svn_url="$2"