tools: add xxd (from vim)

U-Boot requires xxd to create the default environment from an external
file as done in uboot-mediatek.
Build xxd (only, not the rest of vim) as part of tools to make sure it
is present on the buildhost.

Reported-by: David Bauer <mail@david-bauer.net>
Signed-off-by: Daniel Golle <daniel@makrotopia.org>

tools/Makefile

@@ -25,7 +25,7 @@ tools-y += autoconf autoconf-archive automake bc bison cmake cpio dosfstools
 tools-y += e2fsprogs fakeroot findutils firmware-utils flex gengetopt
 tools-y += libressl libtool lzma m4 make-ext4fs missing-macros mkimage
 tools-y += mklibs mm-macros mtd-utils mtools padjffs2 patch-image
-tools-y += patchelf pkgconf quilt squashfskit4 sstrip zip zlib zstd
+tools-y += patchelf pkgconf quilt squashfskit4 sstrip xxd zip zlib zstd
 tools-$(BUILD_B43_TOOLS) += b43-tools
 tools-$(BUILD_ISL) += isl
 tools-$(BUILD_TOOLCHAIN) += expat gmp libelf mpc mpfr

tools/xxd/Makefile

@@ -0,0 +1,33 @@
+# SPDX-License-Identifier: GPL-2.0-or-later
+
+include $(TOPDIR)/rules.mk
+
+PKG_NAME:=xxd
+PKG_SOURCE_NAME:=vim
+PKG_VERSION:=8.2
+PKG_RELEASE:=2
+VIMVER:=82
+
+PKG_SOURCE:=$(PKG_SOURCE_NAME)-$(PKG_VERSION).tar.bz2
+PKG_SOURCE_URL:=http://ftp.vim.org/pub/vim/unix
+PKG_HASH:=f087f821831b4fece16a0461d574ccd55a8279f64d635510a1e10225966ced3b
+PKG_CPE_ID:=cpe:/a:vim:vim
+
+HOST_BUILD_DIR:=$(BUILD_DIR_HOST)/$(PKG_SOURCE_NAME)$(VIMVER)
+HOST_BUILD_PARALLEL:=1
+
+include $(INCLUDE_DIR)/host-build.mk
+
+define Host/Configure
+endef
+
+define Host/Compile
+	$(HOST_MAKE_VARS) $(MAKE) -C $(HOST_BUILD_DIR)/src/xxd
+endef
+
+define Host/Install
+	$(INSTALL_DIR) $(STAGING_DIR_HOST)/bin/
+	$(INSTALL_BIN) $(HOST_BUILD_DIR)/src/xxd/xxd $(STAGING_DIR_HOST)/bin/
+endef
+
+$(eval $(call HostBuild))