dependencies: check core dependencies before anything else

Currently, the dependencies target (that runs dependencies.sh) depends on
DEPENDENCIES_HOST_PREREQ. This means that the dependencies listed in
DEPENDENCIES_HOST_PREREQ (currently host-sstrip if sstrip is selected) are
built *before* the dependencies.sh script is run.

As a result, if e.g. there is no gcc compiler present on the build system, the
dependencies in DEPENDENCIES_HOST_PREREQ will fail to build, and buildroot
will fail non-gracefully.

This patch makes sure that the DEPENDENCIES_HOST_PREREQ are checked *after* the
dependencies.sh script, so that any problem in the build system is reported in
a clean way by dependencies.sh.

Signed-off-by: Thomas De Schampheleire <thomas.de.schampheleire@gmail.com>
Acked-by: Arnout Vandecappelle (Essensium/Mind) <arnout@mind.be>
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>

toolchain/dependencies/dependencies.mk

@@ -16,12 +16,14 @@ DL_TOOLS = \
 	$(findstring git,$(DL_TOOLS_DEPENDENCIES)) \
 	$(findstring bzr,$(DL_TOOLS_DEPENDENCIES))
 
-dependencies: $(DEPENDENCIES_HOST_PREREQ)
+core-dependencies:
 	@HOSTCC="$(firstword $(HOSTCC))" MAKE="$(MAKE)" \
 		CONFIG_FILE="$(CONFIG_DIR)/.config" \
 		DL_TOOLS="$(DL_TOOLS)" \
 		$(TOPDIR)/toolchain/dependencies/dependencies.sh
 
+dependencies: core-dependencies $(DEPENDENCIES_HOST_PREREQ)
+
 dependencies-source:
 
 dependencies-clean:
@@ -35,5 +37,5 @@ dependencies-dirclean:
 # Toplevel Makefile options
 #
 #############################################################
-.PHONY: dependencies
+.PHONY: dependencies core-dependencies