Update 'make doc' to only ronn build if necessary

Also, updated to play nicely with 'make -j8 doc'

Makefile

@@ -53,12 +53,14 @@ clean: doc-clean uninstall
 uninstall: submodules
 	node cli.js rm npm -g -f
 
-doc: node_modules/ronn $(mandocs) $(htmldocs)
+doc: $(mandocs) $(htmldocs)
 
 docclean: doc-clean
 doc-clean:
 	rm -rf \
     node_modules/ronn \
+    node_modules/.bin/ronn \
+		.building_ronn \
     doc/cli/index.md \
     doc/api/index.md \
     $(api_mandocs) \
@@ -67,9 +69,6 @@ doc-clean:
     $(cli_htmldocs) \
 		&>/dev/null || true
 
-node_modules/ronn:
-	node cli.js install git+https://github.com/isaacs/ronnjs.git
-
 # use `npm install ronn` for this to work.
 man/man1/README.1: README.md scripts/doc-build.sh package.json
 	scripts/doc-build.sh $< $@
@@ -94,6 +93,9 @@ html/api/%.html: doc/api/%.md html/dochead.html html/docfoot.html scripts/doc-bu
 doc/cli/index.md: $(markdowns) scripts/index-build.js scripts/doc-build.sh package.json
 	node scripts/index-build.js > $@
 
+node_modules/ronn:
+	node cli.js install https://github.com/isaacs/ronnjs/tarball/master
+
 doc: man
 
 man: $(cli_docs) $(api_docs)

package.json

@@ -49,7 +49,8 @@
   , "request"
   , "proto-list"
   , "which" ]
-, "devDependencies" : { "ronn" : "" }
+, "devDependencies" :
+  { "ronn" : "https://github.com/isaacs/ronnjs/tarball/master" }
 , "engines" : { "node" : "0.4 || 0.5", "npm" : "1" }
 , "scripts" : { "test" : "./test/run"
               , "prepublish" : "make doc"

scripts/doc-build.sh

@@ -6,7 +6,25 @@ fi
 set -o errexit
 set -o pipefail
 
-[ -x ./node_modules/.bin/ronn ] || node cli.js install ronn
+if ! [ -x node_modules/.bin/ronn ]; then
+  if [ -f .building_ronn ]; then
+    while [ -f .building_ronn ]; do
+      sleep 1
+    done
+  else
+    # a race to see which make process will be the one to install ronn
+    echo $$ > .building_ronn
+    sleep 1
+    if [ $(cat .building_ronn) == $$ ]; then
+      make node_modules/ronn
+      rm .building_ronn
+    else
+      while [ -f .building_ronn ]; do
+        sleep 1
+      done
+    fi
+  fi
+fi
 
 src=$1
 dest=$2