Add basic .pkg installer script

Add a simple flat-package installer with postinstall script
to configure the user's system gitconfig.

Author: mjcheetham

.gitignore

@@ -331,3 +331,7 @@ ASALocalRun/
 
 # macOS Finder files
 .DS_Store
+
+# GCM build output
+out/
+

macos/installer/build-installer.sh

@@ -0,0 +1,75 @@
+#!/bin/bash
+
+# Product information
+NAME="Git Credential Manager"
+IDENTIFIER="com.microsoft.GitCredentialManager"
+INSTALL_LOCATION="/usr/local/share/gcm-core"
+
+# Directories
+THISDIR="$( cd "$(dirname "$0")" ; pwd -P )"
+ROOT="$( cd $THISDIR/../.. ; pwd -P )"
+OUT=$ROOT/out
+PKGSCRIPTS=$ROOT/macos/installer/scripts
+MACOUT=$OUT/macos
+INSTALLEROUT=$MACOUT/installer/
+PKGPAYLOAD=$INSTALLEROUT/payload
+
+# Parse script arguments
+for i in "$@"
+do
+case $i in
+    -v=*|--version=*)
+    VERSION="${i#*=}"
+    shift # past argument=value
+    ;;
+    -c=*|--configuration=*)
+    CONFIGURATION="${i#*=}"
+    shift # past argument=value
+    ;;
+    *)
+          # unknown option
+    ;;
+esac
+done
+
+# Set default arguments
+VERSION=${VERSION:=1.0}
+CONFIGURATION=${CONFIGURATION:=Release}
+
+# Ensure output directories exist
+mkdir -p $MACOUT $PKGPAYLOAD
+
+# Publish the core product
+dotnet publish --runtime osx-x64 --configuration $CONFIGURATION --output $PKGPAYLOAD $ROOT/common/src/Git-Credential-Manager
+
+# Build the native credential helpers
+pod install --project-directory=$ROOT/macos/Microsoft.Authentication.Helper
+xcodebuild \
+    -workspace $ROOT/macos/Microsoft.Authentication.Helper/Microsoft.Authentication.Helper.xcworkspace \
+    -scheme Microsoft.Authentication.Helper \
+    -configuration $CONFIGURATION \
+    -derivedDataPath $MACOUT/Microsoft.Authentication.Helper
+
+# Copy helper executables to payload directory
+cp $MACOUT/Microsoft.Authentication.Helper/Build/Products/$CONFIGURATION/Microsoft.Authentication.Helper $PKGPAYLOAD
+
+# Copy uninstaller script
+cp $ROOT/macos/installer/uninstall-gcm.sh $PKGPAYLOAD
+
+# Remove any unwanted .DS_Store files
+find $PKGPAYLOAD -name '*.DS_Store' -type f -delete
+
+# Set full read, write, execute permissions for owner and just read and execute permissions for group and other
+/bin/chmod -R 755 $PKGPAYLOAD
+
+# Remove any extended attributes (ACEs)
+/usr/bin/xattr -rc $PKGPAYLOAD
+
+# Build installer package
+/usr/bin/pkgbuild \
+    --root $PKGPAYLOAD/ \
+    --install-location "$INSTALL_LOCATION" \
+    --scripts $PKGSCRIPTS/ \
+    --identifier "$IDENTIFIER" \
+    --version "$VERSION" \
+    "$INSTALLEROUT/$NAME.pkg"

macos/installer/scripts/configure-git.sh

@@ -0,0 +1,14 @@
+#!/bin/bash
+set -e
+
+# When we're invoked from the macOS Installer, PATH is that of root's
+# Even invoking `launchctl asuser` or `su` the PATH remains the same
+# because the user's profile has not been run.
+# To ensure we have the user's correct PATH we run `path_helper` first.
+PATH=""
+eval $(/usr/libexec/path_helper -s)
+
+git config --system credential.helper /usr/local/share/gcm-core/git-credential-manager
+git config --system credential.https://dev.azure.com.useHttpPath true
+
+exit 0

macos/installer/scripts/postinstall

@@ -0,0 +1,17 @@
+#!/bin/bash
+set -e
+
+# Make symlink to GCM in /usr/local/bin
+if [ ! -e /usr/local/bin/git-credential-manager ]
+then
+    /bin/ln -s /usr/local/share/gcm-core/git-credential-manager /usr/local/bin/git-credential-manager
+fi
+
+# Set system gitconfig for the current user
+USER_ID=`id -u "${USER}"`
+if [ "${COMMAND_LINE_INSTALL}" = "" ]
+then
+    /bin/launchctl asuser "${USER_ID}" "${PWD}/configure-git.sh"
+fi
+
+exit 0

macos/installer/uninstall-gcm.sh

@@ -0,0 +1,32 @@
+#!/bin/bash
+
+# Unconfigure GCM
+HELPER=`git config --system credential.helper`
+if [ $HELPER = "/usr/local/share/gcm-core/git-credential-manager" ]
+then
+	echo "Resetting credential helper to 'osxkeychain'..."
+	sudo git config --system credential.helper osxkeychain
+else
+	echo "GCM was not configured as the Git credential helper."
+fi
+
+# Remove GCM symlink
+if [ -L /usr/local/bin/git-credential-manager ]
+then
+	echo "Deleting GCM symlink..."
+	rm /usr/local/bin/git-credential-manager
+else
+	echo "No GCM symlink found."
+fi
+
+# Forget package installation/delete receipt
+sudo pkgutil --forget com.microsoft.GitCredentialManager
+
+# Remove application files
+if [ -d /usr/local/share/gcm-core/ ]
+then
+	echo "Deleting GCM application files..."
+	sudo rm -rf /usr/local/share/gcm-core/
+else
+	echo "No GCM application files found."
+fi