patch 8.2.4081: CodeQL reports problem in if_cscope causing it to fail

Problem:    CodeQL reports problem in if_cscope causing it to fail.
Solution:   Use execvp() instead of execl().  Merge the header file into the
            source file. (Ozaki Kiichi, closes #9519)
diff --git a/src/Make_vms.mms b/src/Make_vms.mms
index 54aa4c3..5ee4aab 100644
--- a/src/Make_vms.mms
+++ b/src/Make_vms.mms
@@ -908,7 +908,7 @@
 if_cscope.obj : if_cscope.c vim.h [.auto]config.h feature.h os_unix.h \
  ascii.h keymap.h termdefs.h macros.h structs.h regexp.h \
  gui.h beval.h [.proto]gui_beval.pro option.h ex_cmds.h proto.h \
- errors.h globals.h if_cscope.h
+ errors.h globals.h
 if_xcmdsrv.obj : if_xcmdsrv.c vim.h [.auto]config.h feature.h os_unix.h \
  ascii.h keymap.h termdefs.h macros.h structs.h regexp.h \
  gui.h beval.h [.proto]gui_beval.pro option.h ex_cmds.h proto.h \