feat(ngcc): expose --create-ivy-entry-points option on ivy-ngcc (#33049)

This allows a postinstall hook to generate the same
output as the CLI integration does.

See https://github.com/angular/angular/pull/32999#issuecomment-539937368

PR Close #33049

packages/compiler-cli/ngcc/main-ngcc.ts

@@ -45,6 +45,13 @@ if (require.main === module) {
                 'If specified then only the first matching package.json property will be compiled.',
             type: 'boolean'
           })
+          .option('create-ivy-entry-points', {
+            describe:
+                'If specified then new `*_ivy_ngcc` entry-points will be added to package.json rather than modifying the ones in-place.\n' +
+                'For this to work you need to have custom resolution set up (e.g. in webpack) to look for these new entry-points.\n' +
+                'The Angular CLI does this already, so it is safe to use this option if the project is being built via the CLI.',
+            type: 'boolean'
+          })
           .option('l', {
             alias: 'loglevel',
             describe: 'The lowest severity logging message that should be output.',
@@ -65,6 +72,7 @@ if (require.main === module) {
   const propertiesToConsider: string[] = options['p'];
   const targetEntryPointPath = options['t'] ? options['t'] : undefined;
   const compileAllFormats = !options['first-only'];
+  const createNewEntryPointFormats = options['create-ivy-entry-points'];
   const logLevel = options['l'] as keyof typeof LogLevel | undefined;
 
   (async() => {
@@ -76,6 +84,7 @@ if (require.main === module) {
         propertiesToConsider,
         targetEntryPointPath,
         compileAllFormats,
+        createNewEntryPointFormats,
         logger,
         async: true,
       });