[mcast] default multicast feature across all crates + merge main (includes #189)

Enable multicast by default so the packaged artifacts include multicast
support without requiring explicit feature flags at build time.

Author: zeeshanlakhani

.github/buildomat/jobs/image.sh

@@ -101,7 +101,7 @@ pfexec chown "$UID" /out
 
 banner "P4 Codegen"
 # Add gcc-12 so the p4 compiler can find cpp
-PATH=/opt/gcc-12/bin:$PATH cargo xtask codegen --stages $TOFINO_STAGES
+PATH=/opt/gcc-12/bin:$PATH cargo xtask codegen --stages $TOFINO_STAGES --multicast
 
 # Preserve all the diagnostics spit out by the compiler
 mkdir -p /out/p4c-diags

.github/buildomat/jobs/multicast-test.sh

@@ -30,5 +30,4 @@ set -o errexit
 set -o pipefail
 set -o xtrace
 
-export MULTICAST=1
 source .github/buildomat/packet-test-common.sh

.github/buildomat/packet-test-common.sh

@@ -8,16 +8,11 @@ export WS=$wd
 MODEL_STARTUP_TIMEOUT=${MODEL_STARTUP_TIMEOUT:=5}
 STARTUP_TIMEOUT=${STARTUP_TIMEOUT:=120}
 
-if [ x$MULTICAST == x ]; then
-        BUILD_FEATURES=tofino_asic
-	CODEGEN_FEATURES=
-        SWADM_FEATURES=
-    else
-        BUILD_FEATURES=tofino_asic,multicast
-	CODEGEN_FEATURES=--multicast
-        SWADM_FEATURES=--features=multicast
-fi
-    
+BUILD_FEATURES=tofino_asic
+
+CODEGEN_FEATURES=--multicast
+SWADM_FEATURES="--features=multicast"
+
 function cleanup {
     set +o errexit
     set +o pipefail