FORTH and JIT compiler fighting over memory above heapmark for temp buffer space

Have FORTH trya nd reserve space for temp string and PAD away from potential JIT interference

src/toolsrc/plforth.pla

@@ -15,6 +15,7 @@ byte  srclevel   = 0
 //
 // Internal buffers
 //
+word                      strbuf, padbuf
 res[SRCREFS * INBUF_SIZE] inbuf
 res[t_except]             exitforth
 //
@@ -1165,7 +1166,7 @@ def _fill_(a,b,c)#0
   memset(a, c | (c << 8), b)
 end
 def _pad_#1
-  return heapmark + 128
+  return padbuf
 end
 def _trailing_(a,b)#2
   while b and ^(a + b - 1) == ' '
@@ -1639,8 +1640,8 @@ def _str_#0
     _compword_(@d_slit)
     memcpy(heapalloc(len), str, len) // Add to dictionary
   else
-    (@push)(heapmark)#0
-    memcpy(heapmark, str, len) // Copy to HERE
+    (@push)(strbuf)#0
+    memcpy(strbuf, str, len) // Copy to HERE
   fin
 end
 def _type_(a,b)#0
@@ -1977,6 +1978,8 @@ loop
 _estkl = ^(@syscall + 1) // Hack to fill in parameter stack locations
 _estkh = ^(@syscall + 3)
 fileio:iobufalloc(4) // Allocate a bunch of file buffers
+strbuf = heapalloc(256)
+padbuf = heapalloc(256)
 startheap = heapmark
 coldstart
 //