1 files changed, 108 insertions, 0 deletions
diff --git a/include/prereq.mk b/include/prereq.mk
new file mode 100644
index 0000000..6cb590e
--- /dev/null
+++ b/include/prereq.mk
@@ -0,0 +1,108 @@
+#
+# Copyright (C) 2006-2015 OpenWrt.org
+#
+# This is free software, licensed under the GNU General Public License v2.
+# See /LICENSE for more information.
+#
+
+ifneq ($(__prereq_inc),1)
+__prereq_inc:=1
+
+prereq:
+	if [ -f $(TMP_DIR)/.prereq-error ]; then \
+		echo; \
+		cat $(TMP_DIR)/.prereq-error; \
+		rm -f $(TMP_DIR)/.prereq-error; \
+		echo; \
+		false; \
+	fi
+
+.SILENT: prereq
+endif
+
+PREREQ_PREV=
+
+# 1: display name
+# 2: error message
+define Require
+  export PREREQ_CHECK=1
+  ifeq ($$(CHECK_$(1)),)
+    prereq: prereq-$(1)
+
+    prereq-$(1): $(if $(PREREQ_PREV),prereq-$(PREREQ_PREV)) FORCE
+		printf "Checking '$(1)'... "
+		if $(NO_TRACE_MAKE) -f $(firstword $(MAKEFILE_LIST)) check-$(1) >/dev/null 2>/dev/null; then \
+			echo 'ok.'; \
+		else \
+			echo 'failed.'; \
+			echo "$(PKG_NAME): $(strip $(2))" >> $(TMP_DIR)/.prereq-error; \
+		fi
+
+    check-$(1): FORCE
+	  $(call Require/$(1))
+    CHECK_$(1):=1
+
+    .SILENT: prereq-$(1) check-$(1)
+    .NOTPARALLEL:
+  endif
+
+  PREREQ_PREV=$(1)
+endef
+
+
+define RequireCommand
+  define Require/$(1)
+    which $(1)
+  endef
+
+  $$(eval $$(call Require,$(1),$(2)))
+endef
+
+define RequireHeader
+  define Require/$(1)
+    [ -e "$(1)" ]
+  endef
+
+  $$(eval $$(call Require,$(1),$(2)))
+endef
+
+define QuoteHostCommand
+'$(subst ','"'"',$(strip $(1)))'
+endef
+
+# 1: display name
+# 2: failure message
+# 3: test
+define TestHostCommand
+  define Require/$(1)
+	($(3)) >/dev/null 2>/dev/null
+  endef
+
+  $$(eval $$(call Require,$(1),$(2)))
+endef
+
+# 1: canonical name
+# 2: failure message
+# 3+: candidates
+define SetupHostCommand
+  define Require/$(1)
+	[ -f "$(STAGING_DIR_HOST)/bin/$(strip $(1))" ] && exit 0; \
+	for cmd in $(call QuoteHostCommand,$(3)) $(call QuoteHostCommand,$(4)) \
+	           $(call QuoteHostCommand,$(5)) $(call QuoteHostCommand,$(6)) \
+	           $(call QuoteHostCommand,$(7)) $(call QuoteHostCommand,$(8)) \
+			   $(call QuoteHostCommand,$(9)); do \
+		if [ -n "$$$$$$$$cmd" ]; then \
+			bin="$$$$$$$$(PATH="$(subst $(space),:,$(filter-out $(STAGING_DIR_HOST)/%,$(subst :,$(space),$(PATH))))" \
+				which "$$$$$$$${cmd%% *}")"; \
+			if [ -x "$$$$$$$$bin" ] && eval "$$$$$$$$cmd" >/dev/null 2>/dev/null; then \
+				mkdir -p "$(STAGING_DIR_HOST)/bin"; \
+				ln -sf "$$$$$$$$bin" "$(STAGING_DIR_HOST)/bin/$(strip $(1))"; \
+				exit 0; \
+			fi; \
+		fi; \
+	done; \
+	exit 1
+  endef
+
+  $$(eval $$(call Require,$(1),$(if $(2),$(2),Missing $(1) command)))
+endef