remove package mingwrt-dll because mingwm10.dll isn't needed on supported Windows versions anymore

src/mingwrt-dll.mk

@@ -1,25 +0,0 @@
-# This file is part of mingw-cross-env.
-# See doc/index.html for further information.
-
-# MinGW Runtime DLL
-PKG             := mingwrt-dll
-$(PKG)_IGNORE   :=
-$(PKG)_VERSION  := 3.18
-$(PKG)_CHECKSUM := 5ecc6db65849cfe2af2ab6226e55bd7ebf704f00
-$(PKG)_SUBDIR   := .
-$(PKG)_FILE     := mingwrt-$($(PKG)_VERSION)-mingw32-dll.tar.gz
-$(PKG)_WEBSITE  := http://mingw.sourceforge.net/
-$(PKG)_URL      := http://$(SOURCEFORGE_MIRROR)/project/mingw/MinGW Runtime/mingwrt-$($(PKG)_VERSION)/$($(PKG)_FILE)
-$(PKG)_DEPS     :=
-
-define $(PKG)_UPDATE
-    $(call SOURCEFORGE_FILES,http://sourceforge.net/projects/mingw/files/MinGW Runtime/) | \
-    $(SED) -n 's,.*mingwrt-\([0-9][^>]*\)-mingw32-dll\.tar.*,\1,p' | \
-    tail -1
-endef
-
-define $(PKG)_BUILD
-    $(INSTALL) -d '$(PREFIX)/$(TARGET)'
-    cd '$(1)' && \
-        cp -rpv bin '$(PREFIX)/$(TARGET)'
-endef