Rename FALLBACK_DOWNLOAD_PATH to PRIORITY_DOWNLOAD_PATH

Closes #1621.

depends/Makefile

@@ -5,7 +5,7 @@ BASE_CACHE ?= $(BASEDIR)/built
 SDK_PATH ?= $(BASEDIR)/SDKs
 NO_WALLET ?=
 NO_UPNP ?=
-FALLBACK_DOWNLOAD_PATH ?= https://z.cash/depends-sources
+PRIORITY_DOWNLOAD_PATH ?= https://z.cash/depends-sources
 
 BUILD ?= $(shell ./config.guess)
 HOST ?= $(BUILD)

depends/README.md

@@ -33,7 +33,7 @@ The following can be set when running make: make FOO=bar
     SOURCES_PATH: downloaded sources will be placed here
     BASE_CACHE: built packages will be placed here
     SDK_PATH: Path where sdk's can be found (used by OSX)
-    FALLBACK_DOWNLOAD_PATH: If a source file can't be fetched, try here before giving up
+    PRIORITY_DOWNLOAD_PATH: Try fetching source files from here before using their own URLs
     NO_WALLET: Don't download/build/cache libs needed to enable the wallet
     NO_UPNP: Don't download/build/cache packages needed for enabling upnp
     DEBUG: disable some optimizations and enable more runtime checking

depends/funcs.mk

@@ -22,7 +22,7 @@ endef
 define fetch_file
 (test -f $$($(1)_source_dir)/$(4) || \
   ( mkdir -p $$($(1)_download_dir) && echo Fetching $(1)... && \
-  ( $(build_DOWNLOAD) "$$($(1)_download_dir)/$(4).temp" "$(FALLBACK_DOWNLOAD_PATH)/$(4)" || \
+  ( $(build_DOWNLOAD) "$$($(1)_download_dir)/$(4).temp" "$(PRIORITY_DOWNLOAD_PATH)/$(4)" || \
     $(build_DOWNLOAD) "$$($(1)_download_dir)/$(4).temp" "$(2)/$(3)" ) && \
     echo "$(5)  $$($(1)_download_dir)/$(4).temp" > $$($(1)_download_dir)/.$(4).hash && \
     $(build_SHA256SUM) -c $$($(1)_download_dir)/.$(4).hash && \