vim-patch:8.1.0091: MS-Windows: Cannot interrupt gdb when program is running

Problem:    MS-Windows: Cannot interrupt gdb when program is running.
Solution:   Add debugbreak() and use it in the terminal debugger.
            Respect 'modified' in a prompt buffer.
4551c0a9fc

src/nvim/eval.c

@@ -7315,9 +7315,7 @@ dict_T *get_win_info(win_T *wp, int16_t tpnr, int16_t winnr)
   return dict;
 }
 
-/*
- * Find window specified by "vp" in tabpage "tp".
- */
+// Find window specified by "vp" in tabpage "tp".
 win_T *
 find_win_by_nr(
     typval_T *vp,

src/nvim/eval.lua

@@ -82,6 +82,7 @@ return {
     ctxset={args={1, 2}},
     ctxsize={},
     cursor={args={1, 3}},
+    debugbreak={args={1, 1}},
     deepcopy={args={1, 2}},
     delete={args={1,2}},
     deletebufline={args={2,3}},

src/nvim/eval/funcs.c

@@ -1408,9 +1408,31 @@ static void f_cursor(typval_T *argvars, typval_T *rettv, FunPtr fptr)
   rettv->vval.v_number = 0;
 }
 
-/*
- * "deepcopy()" function
- */
+// "debugbreak()" function
+static void f_debugbreak(typval_T *argvars, typval_T *rettv, FunPtr fptr)
+{
+  int pid;
+
+  rettv->vval.v_number = FAIL;
+  pid = (int)tv_get_number(&argvars[0]);
+  if (pid == 0) {
+    EMSG(_(e_invarg));
+  } else {
+#ifdef WIN32
+    HANDLE hProcess = OpenProcess(PROCESS_ALL_ACCESS, 0, pid);
+
+    if (hProcess != NULL) {
+      DebugBreakProcess(hProcess);
+      CloseHandle(hProcess);
+      rettv->vval.v_number = OK;
+    }
+#else
+    uv_kill(pid, SIGINT);
+#endif
+  }
+}
+
+// "deepcopy()" function
 static void f_deepcopy(typval_T *argvars, typval_T *rettv, FunPtr fptr)
 {
   int noref = 0;

src/nvim/undo.c

@@ -2971,7 +2971,10 @@ static char_u *u_save_line(linenr_T lnum)
 bool bufIsChanged(buf_T *buf)
   FUNC_ATTR_NONNULL_ALL FUNC_ATTR_WARN_UNUSED_RESULT
 {
-  return !bt_dontwrite(buf) && (buf->b_changed || file_ff_differs(buf, true));
+  // In a "prompt" buffer we do respect 'modified', so that we can control
+  // closing the window by setting or resetting that option.
+  return  (!bt_dontwrite(buf) || bt_prompt(buf))
+    && (buf->b_changed || file_ff_differs(buf, true));
 }
 
 // Return true if any buffer has changes.  Also buffers that are not written.