[FIX] Armhf snap build (#11268)

* Update snapcraft.yaml

* Add node prep script

* Make executable

* Remove devDependency that caused arm failure.  Also removed packaged binary for sharp for arm

* dev/null tar stdout.  Remove sharp vendor folder only for arm so it will download and build

* add missing slash

* fix arm check to catch armv7l also

* remove /dev/null and verbose flag.

* Move extract to new line

.snapcraft/resources/prepareRocketChat

@@ -2,11 +2,18 @@
 
 curl -SLf "https://releases.rocket.chat/#{RC_VERSION}/download/" -o rocket.chat.tgz
 
-tar xvf rocket.chat.tgz --strip 1
+tar xf rocket.chat.tgz --strip 1
 
 cd programs/server
+rm -rf npm/node_modules/meteor/emojione_emojione/node_modules/grunt-contrib-qunit
 
-npm install
+if [[ $(uname -m) == *armv6l* ]] || [[ $(uname -m) == *armv7l* ]]
+then
+  rm -rf npm/node_modules/sharp/vendor
+fi
+
+export NODE_ENV=production
+npm i
 
 # Ideally this will go away.  For some reason on install its installing node-v57-linux-x64-glibc but when actually running it is looking for node-v57-linux-x64-unknown
 if [[ $(uname -m) == "x86_64" ]]
@@ -15,4 +22,5 @@ then
 fi
 
 # sharp needs execution stack removed - https://forum.snapcraft.io/t/snap-and-executable-stacks/1812
-execstack --clear-execstack npm/node_modules/sharp/vendor/lib/librsvg-2.so.2.42.0
+ls -l npm/node_modules/sharp/vendor
+execstack --clear-execstack npm/node_modules/sharp/vendor/lib/librsvg-2.so*

.snapcraft/resources/preparenode

@@ -0,0 +1,23 @@
+#!/bin/bash
+
+node_version="v8.11.3"
+
+unamem="$(uname -m)"
+if [[ $unamem == *aarch64* ]]; then
+        node_arch="arm64"
+elif [[ $unamem == *64* ]]; then
+        node_arch="x64"
+elif [[ $unamem == *86* ]]; then
+        node_arch="x86"
+elif [[ $unamem == *armv6l* ]]; then
+        node_arch="armv6l"
+elif [[ $unamem == *armv7l* ]]; then
+        node_arch="armv7l"
+else
+        echo "Aborted, unsupported or unknown architecture: $unamem"
+        return 2
+fi
+
+
+wget https://nodejs.org/dist/$node_version/node-$node_version-linux-$node_arch.tar.xz
+tar xf node-$node_version-linux-$node_arch.tar.xz --strip 1

.snapcraft/snapcraft.yaml

@@ -39,7 +39,7 @@ apps:
 parts:
     node:
         plugin: dump 
-        prepare: wget https://nodejs.org/dist/v8.11.2/node-v8.11.2-linux-x64.tar.xz; tar xvf node-v8.11.2-linux-x64.tar.xz --strip 1; 
+        prepare: ./resources/preparenode  
         build-packages:
             # For fibers
             - python