patch 9.1.0623: Mingw: errors when trying to delete non-existing files

Problem:  Mingw: warnings when trying to delete non-existing files
Solution: Use "rm -f" instead of "rm" to suppress errors for
          non-existing files (Ken Takata)

closes: #15350

Signed-off-by: Ken Takata <kentkt@csc.jp>
Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/src/Make_cyg_ming.mak b/src/Make_cyg_ming.mak
index a0c10b1..bd9d0ac 100644
--- a/src/Make_cyg_ming.mak
+++ b/src/Make_cyg_ming.mak
@@ -184,7 +184,7 @@
  ifndef CROSS_COMPILE
 CROSS_COMPILE = i586-pc-mingw32msvc-
  endif
-DEL = rm
+DEL = rm -f
 MKDIR = mkdir -p
 DIRSLASH = /
 else
@@ -212,7 +212,7 @@
 # In this case, unix-like commands can be used.
 #
  ifneq (sh.exe, $(SHELL))
-DEL = rm
+DEL = rm -f
 MKDIR = mkdir -p
 DIRSLASH = /
  else