Jenkins cross platform updates

This changes our cross plat build to install the desired version of Mono
on the machine as a part of the CI process.  This lowers the management
overhead of our Mac / Linux machines as we can use any machine in the pool
vs. having reserved, and custom maintained, machines for Roslyn.

cibuild.sh

@@ -14,6 +14,7 @@ usage()
 XUNIT_VERSION=2.0.0-alpha-build2576
 FULL_RUN=true
 OS_NAME=$(uname -s)
+
 while [[ $# > 0 ]]
 do
     opt="$1"
@@ -132,6 +133,57 @@ build_roslyn()
     fi
 }
 
+# Install the specified Mono toolset from our Azure blob storage.
+install_mono_toolset()
+{
+    TARGET=/tmp/$1
+    echo "Installing Mono toolset $1"
+    if [ -d $TARGET ]; then
+        echo "Already installed"
+        return
+    fi
+
+    pushd /tmp
+
+    rm $TARGET 2>/dev/null
+    curl -O https://dotnetci.blob.core.windows.net/roslyn/$1.tar.bz2
+    tar -jxf $1.tar.bz2
+    if [ $? -ne 0 ]; then
+        echo "Unable to download toolset"
+        exit 1
+    fi
+
+    popd
+}
+
+# This function will update the PATH variable to put the desired
+# version of Mono ahead of the system one. 
+set_mono_path()
+{
+    if [ "$CUSTOM_MONO_PATH" != "" ]; then
+        if [ ! -d "$CUSTOM_MONO_PATH" ]; then
+            echo "Not a valid directory $CUSTOM_MONO_PATH"
+            exit 1
+        fi
+  
+        echo "Using mono path $CUSTOM_MONO_PATH"
+        PATH=$CUSTOM_MONO_PATH:$PATH
+        return
+    fi
+
+    if [ "$OS_NAME" = "Darwin" ]; then
+        MONO_TOOLSET_NAME=mono.mac.1
+    elif [ "$OS_NAME" = "Linux" ]; then
+        MONO_TOOLSET_NAME=mono.linux.1
+    else
+        echo "Error: Unsupported OS $OS_NAME"
+        exit 1
+    fi
+
+    install_mono_toolset $MONO_TOOLSET_NAME
+    PATH=/tmp/$MONO_TOOLSET_NAME/bin:$PATH
+}
+
 test_roslyn()
 {
     if [ "$FULL_RUN" != "true" ]; then
@@ -170,23 +222,6 @@ if [ "$OS_NAME" = "Linux" ]; then
     FULL_RUN=false
 fi
 
-if [ "$CUSTOM_MONO_PATH" != "" ]; then
-    if [ ! -d "$CUSTOM_MONO_PATH" ]; then
-        echo "Not a valid directory $CUSTOM_MONO_PATH"
-        exit 1
-    fi
-
-    echo "Using mono path $CUSTOM_MONO_PATH"
-    PATH=$CUSTOM_MONO_PATH:$PATH
-else
-    echo Changing mono snapshot
-    . mono-snapshot mono/20150316155603
-    if [ $? -ne 0 ]; then
-        echo Could not set mono snapshot 
-        exit 1
-    fi
-fi
-
 # NuGet on mono crashes about every 5th time we run it.  This is causing
 # Linux runs to fail frequently enough that we need to employ a 
 # temporary work around.  
@@ -194,6 +229,8 @@ echo Restoring NuGet packages
 run_nuget restore src/Roslyn.sln
 run_nuget install xunit.runners -PreRelease -Version $XUNIT_VERSION -OutputDirectory packages
 
+set_mono_path
+which mono
 compile_toolset
 save_toolset
 clean_roslyn

docs/infrastructure/mono-toolset.md

+Building a new Mono toolset
+====
+This document describes building a new Mono toolset for use in our Mac or Linux Jenkins jobs.  
+
+### Building
+The new *toolset name* will be chosen as one of the following:
+
+- Linux: mono.linux.`<version number>`
+- Mac: mono.mac.`<version number>`
+
+The value of *version number* will simply be the one number higher than the current version number of the toolset.  
+
+To build the toolset execute the following:
+
+- Set `$PREFIX` to `/tmp/<toolset name>`
+- Follow the remainder of the [Compiling Mono](http://www.mono-project.com/docs/compiling-mono/) instructions.  
+- Install the PCL references: `<roslyn dir>/build/linux/setup-pcl.sh /tmp/<toolset name>`
+- Bzip the resulting directory.  `tar -jcvf <toolset name>.tar.bz2 /tmp/<toolset name>`
+- Upload the file to the Azure in the dotnetci storage account in the roslyn container.  
+- Send a PR to change [cibuild.sh](https://github.com/dotnet/roslyn/blob/master/cibuild.sh) to use the new toolset.  
+
+Note: This process needs to be repeated for both Mac and Linux.  
+
+### Existing toolsets
+This table describes the existing Mono toolsets and the commit they were built from.  
+
+| Version | Linux | Mac |
+| --- | --- | --- |
+| 1 | [43af8d475d853c8408ddaddbed4cfd61d2919780](https://github.com/jaredpar/mono/commit/43af8d475d853c8408ddaddbed4cfd61d2919780) | [43af8d475d853c8408ddaddbed4cfd61d2919780](https://github.com/jaredpar/mono/commit/43af8d475d853c8408ddaddbed4cfd61d2919780) |