libpldmresponder: Make libpldmresponder optional

libpldmresponder library is for handling incoming PLDM request messages
on BMC. There are usecases for PLDM daemon on BMC where it is primarily
a requester and BMC aggregates information about firmware devices that
implement MCTP/PLDM and facilitate firmware upgrade of the devices.
This patch is a step in that direction to enable PLDM daemon on BMC
primarily as PLDM requester.

Tested: Ran PLDM daemon successfully without libpldmresponder library.

Signed-off-by: Tom Joseph <rushtotom@gmail.com>
Change-Id: Iceaa10127352aaaba6c338d7ea9ac187be4e5fad
diff --git a/meson_options.txt b/meson_options.txt
index e1f6d43..4b1d833 100644
--- a/meson_options.txt
+++ b/meson_options.txt
@@ -4,6 +4,7 @@
 option('oem-ibm', type: 'feature', description: 'Enable IBM OEM PLDM')
 option('requester-api', type: 'feature', description: 'Enable libpldm requester API', value: 'enabled')
 option('utilities', type: 'feature', description: 'Enable debug utilities', value: 'enabled')
+option('libpldmresponder', type: 'feature', description: 'Enable libpldmresponder', value: 'enabled')
 
 option('libpldm-only', type: 'feature', description: 'Only build libpldm', value: 'disabled')
 option('oem-ibm-dma-maxsize', type: 'integer', min:4096, max: 16773120, description: 'OEM-IBM: max DMA size', value: 8384512) #16MB - 4K