tests: Migrate to newlib-nano and libgloss-htif

This deprecates the monolithic syscalls.c environment in favor of a more
structured board support package (BSP) based on newlib.

tests/libgloss.mk

@@ -0,0 +1,50 @@
+# Handle libgloss-htif dependency
+ifndef libgloss
+
+ifndef GCC
+$(error GCC is not defined)
+endif
+
+libgloss_specs := htif_nano.specs
+
+# Test whether libgloss-htif is globally installed and usable
+# Define BUILD_LIBGLOSS=1 to unconditionally force a local build
+BUILD_LIBGLOSS ?= $(shell { echo 'int main(void) { return 0; }' | \
+	$(GCC) -xc -specs=$(libgloss_specs) -o /dev/null - 2> /dev/null ; } || \
+	echo "$$?")
+
+ifneq ($(BUILD_LIBGLOSS),)
+$(info libgloss-htif: Using local build)
+
+libgloss_srcdir := ../toolchains/libgloss
+libgloss_builddir := libgloss
+libgloss_specs := $(libgloss_srcdir)/util/$(libgloss_specs)
+libgloss_lib := $(libgloss_builddir)/libgloss_htif.a
+libgloss := $(libgloss_lib) $(libgloss_specs) htif.ld
+
+LDFLAGS += -L libgloss
+
+$(libgloss_builddir)/Makefile: $(libgloss_srcdir)/configure
+	mkdir -p $(dir $@)
+	cd $(dir $@) && $(realpath $<) \
+		--prefix=$(shell $(GCC) -print-sysroot) \
+		--host=$(TARGET) \
+		--disable-multilib
+
+$(libgloss_lib): $(libgloss_builddir)/Makefile
+	$(MAKE) -C $(dir $^)
+
+.PHONY: libgloss
+libgloss: $(libgloss)
+
+else
+
+$(info libgloss-htif: Using global install)
+libgloss :=  # No additional prerequisites
+
+endif
+
+CFLAGS += -specs=$(libgloss_specs)
+LDFLAGS += -specs=$(libgloss_specs)
+
+endif # libgloss