Initial depends addition

Depends cross compiles project dependencies for linux, mac and windows and multiple architectures.
Depends is original work by Cory Fields and used in bitcoin and a wide range of bitcoin related projects.

contrib/depends/packages/native_ccache.mk

@@ -0,0 +1,25 @@
+package=native_ccache
+$(package)_version=3.3.3
+$(package)_download_path=https://samba.org/ftp/ccache
+$(package)_file_name=ccache-$($(package)_version).tar.bz2
+$(package)_sha256_hash=2985bc5e32ebe38d2958d508eb54ddcad39eed909489c0c2988035214597ca54
+
+define $(package)_set_vars
+$(package)_config_opts=
+endef
+
+define $(package)_config_cmds
+  $($(package)_autoconf)
+endef
+
+define $(package)_build_cmds
+  $(MAKE)
+endef
+
+define $(package)_stage_cmds
+  $(MAKE) DESTDIR=$($(package)_staging_dir) install
+endef
+
+define $(package)_postprocess_cmds
+  rm -rf lib include
+endef