Fix compiler warnings.

Thanks to Demetri Obenour.

src/host/buildvm_fold.c

@@ -9,7 +9,7 @@
 
 /* Context for the folding hash table generator. */
 static int lineno;
-static int funcidx;
+static uint32_t funcidx;
 static uint32_t foldkeys[BUILD_MAX_FOLD];
 static uint32_t nkeys;
 

src/host/genminilua.lua

@@ -300,6 +300,7 @@ local function strip_unused3(src)
   src = gsub(src, "if%([^\n]*hookmask[^\n]*&&\n[^\n]*%b{}\n", "")
   src = gsub(src, "(twoto%b()%()", "%1(size_t)")
   src = gsub(src, "i<sizenode", "i<(int)sizenode")
+  src = gsub(src, "cast%(unsigned int,key%-1%)", "cast(unsigned int,key)-1")
   return gsub(src, "\n\n+", "\n")
 end
 

src/host/minilua.c

@@ -1606,7 +1606,7 @@ luaC_barriert(L,t,key);
 return gval(mp);
 }
 static const TValue*luaH_getnum(Table*t,int key){
-if(cast(unsigned int,key-1)<cast(unsigned int,t->sizearray))
+if(cast(unsigned int,key)-1<cast(unsigned int,t->sizearray))
 return&t->array[key-1];
 else{
 lua_Number nk=cast_num(key);