Add litmus test

Original patch by Dylan O'Donnell

doc/fixes35.0

@@ -897,6 +897,7 @@ allow showing legal positions for stinking cloud, jumping and polearms
 cloned creatures (of any type) don't deathdrop items
 pudding corpses behave somewhat differently than before
 mithril armor should have silver color
+lichen corpse is an acid indicator
 
 
 Platform- and/or Interface-Specific Fixes

include/decl.h

@@ -266,7 +266,7 @@ E NEARDATA struct c_color_names {
     const char	*const c_black, *const c_amber, *const c_golden,
 		*const c_light_blue,*const c_red, *const c_green,
 		*const c_silver, *const c_blue, *const c_purple,
-		*const c_white;
+		*const c_white, *const c_orange;
 } c_color_names;
 #define NH_BLACK		c_color_names.c_black
 #define NH_AMBER		c_color_names.c_amber
@@ -278,6 +278,7 @@ E NEARDATA struct c_color_names {
 #define NH_BLUE			c_color_names.c_blue
 #define NH_PURPLE		c_color_names.c_purple
 #define NH_WHITE		c_color_names.c_white
+#define NH_ORANGE		c_color_names.c_orange
 
 /* The names of the colors used for gems, etc. */
 E const char *c_obj_colors[];

src/decl.c

@@ -216,7 +216,7 @@ NEARDATA struct c_color_names c_color_names = {
 	"black", "amber", "golden",
 	"light blue", "red", "green",
 	"silver", "blue", "purple",
-	"white"
+	"white", "orange"
 };
 
 struct menucoloring *menu_colorings = NULL;

src/potion.c

@@ -1819,6 +1819,15 @@ dodip()
 	    return 1;
 	}
 
+        if(potion->otyp == POT_ACID && obj->otyp == CORPSE &&
+           obj->corpsenm == PM_LICHEN & !Blind) {
+               pline("%s %s %s around the edges.", The(cxname(obj)),
+                     otense(obj, "turn"), potion->odiluted ?
+                     hcolor(NH_ORANGE) : hcolor(NH_RED));
+               potion->in_use = FALSE;    /* didn't go poof */
+               return(1);
+	}
+
 	if(is_poisonable(obj)) {
 	    if(potion->otyp == POT_SICKNESS && !obj->opoisoned) {
 		char buf[BUFSZ];

src/pray.c

@@ -1370,7 +1370,7 @@ dosacrifice()
 		      a_gname(), u_gname());
 		pline("%s is enraged...", u_gname());
 		pline("Fortunately, %s permits you to live...", a_gname());
-		pline(cloud_of_smoke, hcolor("orange"));
+		pline(cloud_of_smoke, hcolor(NH_ORANGE));
 		done(ESCAPED);
 	    } else { /* super big win */
 		adjalign(10);