no sacrificing while swallowed

doc/fixes34.1

@@ -44,6 +44,7 @@ clarify travel command behavior in the Guidebook
 touch_artifact checks needed when snagging w/bullwhip and stealing
 cannot trip over submerged objects if you're water walking
 wand of striking was not identified if it activated a statue trap
+cannot sacrifice while you're swallowed
 
 
 Platform- and/or Interface-Specific Fixes

src/pray.c

@@ -1045,7 +1045,7 @@ dosacrifice()
     int pm;
     aligntyp altaralign = a_align(u.ux,u.uy);
 
-    if (!on_altar()) {
+    if (!on_altar() || u.uswallow) {
 	You("are not standing on an altar.");
 	return 0;
     }