fix noarch in dsm7

simple hack to set os_min_ver to 7.0-4000

build using: make noarch-7.0 or make noarch-6.1
build must be clean between builds

SynoCommunity#4215 (comment)

Author: publicarray

mk/spksrc.spk.mk

@@ -19,6 +19,13 @@ OS_MIN_VER = 3.1-1594
 FIRMWARE = $(OS_MIN_VER)
 endif
 
+ifeq ($(shell expr "$(TCVERSION)" \>= 7.0),1)
+TC_VERS=$(TCVERSION)
+SPK_TCVERS=$(TCVERSION)
+include ../../mk/spksrc.tc-vers.mk
+TC_OS_MIN_VER = $(word 1,$(subst ., ,$(TC_VERS))).$(word 2,$(subst ., ,$(TC_VERS)))-$(TC_BUILD)
+endif
+
 SPK_FILE_NAME = $(PACKAGES_DIR)/$(SPK_NAME)_$(SPK_NAME_ARCH)-$(SPK_TCVERS)_$(SPK_VERS)-$(SPK_REV).spk
 
 #####
@@ -452,6 +459,10 @@ publish-legacy-toolchain-%:
 	done \
 
 ####
+noarch-%:
+	@$(MSG) Building package for noarch $*
+	-@MAKEFLAGS= $(MAKE) ARCH= TCVERSION=$(if $(findstring $*,$(basename $(subst -,.,$(basename $(subst .,,$*))))),$(DEFAULT_TC),$(notdir $(subst -,/,$*)))
+
 
 arch-%:
 	@$(MSG) Building package for arch $*