Support compiling fabric.p4 with non-standard bool declarations

Change-Id: I5e579f58f274996fdff55d8e35d1dd96a7013941
diff --git a/pipelines/fabric/src/main/resources/include/spgw.p4 b/pipelines/fabric/src/main/resources/include/spgw.p4
index 87839f6..640c7cc 100644
--- a/pipelines/fabric/src/main/resources/include/spgw.p4
+++ b/pipelines/fabric/src/main/resources/include/spgw.p4
@@ -143,7 +143,7 @@
     }
 
     apply {
-        spgw_meta.do_spgw = false;
+        spgw_meta.do_spgw = _FALSE;
         if (gtpu.isValid()) {
             // If here, the parsed ipv4 header is the outer GTP one, but
             // fabric needs to forward on the inner one, i.e. this.
@@ -156,15 +156,15 @@
 
             if (s1u_filter_table.apply().hit) {
                 // TODO: check also that gtpu.msgtype == GTP_GPDU
-                spgw_meta.do_spgw = true;
+                spgw_meta.do_spgw = _TRUE;
                 spgw_meta.direction = DIR_UPLINK;
             }
         } else if (ue_filter_table.apply().hit) {
-            spgw_meta.do_spgw = true;
+            spgw_meta.do_spgw = _TRUE;
             spgw_meta.direction = DIR_DOWNLINK;
         }
 
-        if (!spgw_meta.do_spgw) {
+        if (spgw_meta.do_spgw == _FALSE) {
             // Exit this control block.
             return;
         }
@@ -246,7 +246,7 @@
     }
 
     apply {
-        if (spgw_meta.do_spgw && spgw_meta.direction == DIR_DOWNLINK) {
+        if (spgw_meta.do_spgw == _TRUE && spgw_meta.direction == DIR_DOWNLINK) {
             gtpu_encap();
         }
     }