Post-quantum signing utilities

A trio of utilities for generating SPHINCS⁺-SHAKE256-192f signatures.
This is a post-quantum, hash-based signature scheme with 194-bit
security.

It is also a test for using the Nimble package manager for managing Nim
target dependencies.

mk/nimble.mk

@@ -0,0 +1,31 @@
+TARGET     ?= $(lastword $(subst /, ,$(PRG_DIR)))
+NIMBLE_PKG ?= $(TARGET)
+LIBS        = base libc
+
+CC_CXX_WARN_STRICT =
+
+$(TARGET): assemble.tag $(SHARED_LIBS)
+	libs=$(LIB_CACHE_DIR); $(LD_CMD) $(wildcard src/nimcache/*.o) -o $(TARGET)
+	ln -sf $(CURDIR)/$@ $(INSTALL_DIR)/$@
+
+assemble.tag: copy.tag nim.cfg
+	nimble --verbose cpp src/$(TARGET)
+	@touch $@
+
+nim.cfg:
+	rm -f $@
+	echo "-d:nimDebugDlOpen" >> $@
+	echo "--os:genode" >> $@
+	echo "--cpu:$(NIM_CPU)" >> $@
+	echo "--noCppExceptions" >> $@
+	echo "--noLinking" >> $@
+	echo "--passC:\"$(CXX_DEF) $(CC_CXX_OPT) $(INCLUDES) -fpermissive\"" >> $@
+	echo "$(NIM_OPT)" >> $@
+
+NIMBLE_PATH := $(shell nimble path $(NIMBLE_PKG))
+
+copy.tag:
+	nimble install -n https://github.com/ehmry/nim-genode
+	cp -avu $(PRG_DIR)/* .
+
+.PHONY: nim.cfg