Add a local regression Makefile

Travis is both slow and screwy, this lets me run the regressions
locally.

.gitignore

@@ -4,3 +4,4 @@ config.log
 config.status
 Makefile
 .DS_Store
+!/regression/Makefile

regression/.gitignore

@@ -0,0 +1,3 @@
+/build
+/stamps
+/install

regression/Makefile

@@ -0,0 +1,63 @@
+.SECONDARY:
+
+# The list of target tuples that we want to test.
+.PHONY: report
+report: report-newlib-rv32i-ilp32-medlow
+report: report-newlib-rv32im-ilp32-medlow
+report: report-newlib-rv32iac-ilp32-medlow
+report: report-newlib-rv32imac-ilp32-medlow
+report: report-newlib-rv32imafc-ilp32f-medlow
+report: report-newlib-rv64imac-lp64-medlow
+report: report-newlib-rv64imafdc-lp64d-medlow
+report: report-linux-rv32imac-ilp32-medlow
+report: report-linux-rv32imafdc-ilp32-medlow
+report: report-linux-rv32imafdc-ilp32d-medlow
+report: report-linux-rv64imac-lp64-medlow
+report: report-linux-rv64imafdc-lp64-medlow
+report: report-linux-rv64imafdc-lp64d-medlow
+
+# This is the link between the report targets and the actual testsuite
+# build/test runs.
+.PHONY: report-%
+report-%: stamps/check-%
+	$(eval $@_BUILDDIR := build/$(patsubst report-%,%,$(notdir $@)))
+	$(MAKE) -C $($@_BUILDDIR) report
+
+# These rules call into the above Makefile to actually test the various
+# toolchain targets we care about.
+stamps/configure-%:
+	$(eval $@_BUILDDIR := build/$(patsubst configure-%,%,$(notdir $@)))
+	$(eval $@_PREFIX := install/$(patsubst configure-%,%,$(notdir $@)))
+	$(eval $@_LINUX := $(if $(filter linux,$(word 2,$(subst -, ,$(notdir $@)))),--enable-linux,--disable-linux))
+	$(eval $@_MARCH := $(word 3,$(subst -, ,$(notdir $@))))
+	$(eval $@_MABI := $(word 4,$(subst -, ,$(notdir $@))))
+	$(eval $@_MCMODEL := $(word 5,$(subst -, ,$(notdir $@))))
+	mkdir -p $($@_BUILDDIR)
+	cd $($@_BUILDDIR); $(abspath ../configure) \
+		$($@_LINUX) \
+		--disable-multilib \
+		--prefix=$(abspath $($@_PREFIX)) \
+		--with-arch=$($@_MARCH) \
+		--with-abi=$($@_MABI) \
+		--with-cmodel=$($@_MCMODEL)
+	mkdir -p $(dir $@)
+	date > $@
+
+stamps/build-%: stamps/configure-%
+	$(eval $@_BUILDDIR := build/$(patsubst build-%,%,$(notdir $@)))
+	$(eval $@_PREFIX := install/$(patsubst build-%,%,$(notdir $@)))
+	$(MAKE) -C $($@_BUILDDIR)
+	mkdir -p $(dir $@)
+	echo 'export $$PATH="$(abspath $($@_PREFIX)):$$PATH"' > $($@_PREFIX)/enter.bash
+	date > $@
+
+stamps/check-%: stamps/build-%
+	$(eval $@_BUILDDIR := build/$(patsubst check-%,%,$(notdir $@)))
+	$(MAKE) -C $($@_BUILDDIR) check
+	mkdir -p $(dir $@)
+	date > $@
+
+# Cleans up after a run
+.PHONY: clean
+clean::
+	rm -rf build install stamps