add note about vix api libraries

website/source/docs/builders/vmware-iso.html.md

@@ -24,6 +24,10 @@ Linux. It can also build machines directly on [VMware vSphere
 Hypervisor](https://www.vmware.com/products/vsphere-hypervisor/) using SSH as
 opposed to the vSphere API.
 
+-> When using VMWare Player on Linux, you may need to install [VIX API
+libraries](https://www.vmware.com/support/developer/vix-api/) to use the
+`vmrun` utility, which is required by the builder.
+
 The builder builds a virtual machine by creating a new virtual machine from
 scratch, booting it, installing an OS, provisioning software within the OS, then
 shutting it down. The result of the VMware builder is a directory containing all

website/source/docs/builders/vmware-vmx.html.md

@@ -21,6 +21,10 @@ Professional](https://www.vmware.com/products/fusion-professional/) for OS X,
 for Linux and Windows, and [VMware
 Player](https://www.vmware.com/products/player/) on Linux.
 
+-> When using VMWare Player on Linux, you may need to install [VIX API
+libraries](https://www.vmware.com/support/developer/vix-api/) to use the
+`vmrun` utility, which is required by the builder.
+
 The builder builds a virtual machine by cloning the VMX file using the clone
 capabilities introduced in VMware Fusion Professional 6, Workstation 10, and
 Player 6. After cloning the VM, it provisions software within the new machine,