Give PolicyOverride an env and say why Emulation has none

Author: GOB52

.github/workflows/platformio-build-check.yml

@@ -116,6 +116,10 @@ jobs:
             board: Core
             framework: Arduino
             espressif32: latest
+          - example: NFCA_PolicyOverride
+            board: Core
+            framework: Arduino
+            espressif32: latest
           # NFCA Detect on M5Dial with builtin WS1850S
           - example: NFCA_Detect
             board: Dial_Builtin

platformio.ini

@@ -591,6 +591,20 @@ build_src_filter = +<*> -<.git/> -<.svn/>
 build_flags = ${option_release.build_flags}
   -D USING_UNIT_RFID2
 
+;PolicyOverride
+[env:NFCA_PolicyOverride_Core_Arduino_latest]
+extends=Core, option_release, arduino_latest
+build_src_filter = +<*> -<.git/> -<.svn/>
+  +<../examples/UnitUnified/NFCA/PolicyOverride/>
+  -<../examples/UnitUnified/NFCA/PolicyOverride/build/>
+  -<../examples/UnitUnified/NFCA/PolicyOverride/managed_components/>
+build_flags = ${option_release.build_flags}
+  -D USING_UNIT_RFID2
+
+; NFCA Emulation has no env here on purpose: the example refuses WS1850S at compile time
+; (#error "Emulation is NOT supported on UnitRFID2 / M5Dial Builtin"), so it only builds
+; against UnitNFC / CapCC1101, which this library does not drive.
+
 
 ;;;
 ; [env:NFCA_NDEF_Dial_Arduino_latest]