Allocate temp inbuf during BRK handling in FORTH

src/toolsrc/plforth.pla

@@ -776,13 +776,15 @@ def showtrace(dentry)#0
     putln; puts("( "); _prstack_; puts(") "); puts(dentry); putc(' ')
 end
 def brkhandle(dentry)#0
-  word brk_infn, brk_inptr, brk_iip
+  word brk_infn, brk_inptr, brk_iip, brk_inbuf
   byte brk_state
 
   showtrace(dentry)
   brk_iip   = IIP
   brk_infn  = infunc
   brk_inptr = inptr
+  brk_inbuf = keyinbuf
+  keyinbuf  = heapalloc(INBUF_SIZE + 1)
   infunc    = @keyin
   inptr     = keyinbuf
   ^inptr    = 0
@@ -795,6 +797,8 @@ def brkhandle(dentry)#0
   IIP       = brk_iip
   infunc    = brk_infn
   inptr     = brk_inptr
+  heaprelease(keyinbuf)
+  keyinbuf  = brk_inbuf
 end
 //
 // Execute code in CFA