monocypher: add package

A small, auditable, portable cryptographic library. It provides the
BLAKE2b and Ed25519 primitives that an mbedTLS-based libssh lacks, so
comrade can follow that backend without pulling in libcrypto.

Signed-off-by: Daniel Golle <daniel@makrotopia.org>

libs/monocypher/Makefile

@@ -0,0 +1,68 @@
+#
+# Copyright (C) 2026 Daniel Golle <daniel@makrotopia.org>
+#
+# This is free software, licensed under the GNU General Public License v2.
+# See /LICENSE for more information.
+#
+
+include $(TOPDIR)/rules.mk
+
+PKG_NAME:=monocypher
+PKG_VERSION:=4.0.3
+PKG_RELEASE:=1
+
+PKG_SOURCE:=$(PKG_NAME)-$(PKG_VERSION).tar.gz
+PKG_SOURCE_URL:=https://monocypher.org/download
+PKG_HASH:=8cc9bc341a66249016db9bd70e9142d8d0aef9945973744b1ac05dbc55d8ee66
+
+PKG_MAINTAINER:=Daniel Golle <daniel@makrotopia.org>
+PKG_LICENSE:=BSD-2-Clause OR CC0-1.0
+PKG_LICENSE_FILES:=LICENCE.md
+
+PKG_BUILD_FLAGS:=gc-sections
+PKG_BUILD_PARALLEL:=1
+PKG_INSTALL:=1
+
+include $(INCLUDE_DIR)/package.mk
+
+define Package/libmonocypher
+  SECTION:=libs
+  CATEGORY:=Libraries
+  TITLE:=Small, auditable, portable cryptographic library
+  URL:=https://monocypher.org/
+  ABI_VERSION:=4
+endef
+
+define Package/libmonocypher/description
+  Monocypher is a small, portable, easy to use cryptographic library in
+  about 2000 lines of C99. It provides authenticated encryption
+  (XChaCha20-Poly1305), hashing (BLAKE2b, SHA-512), password hashing
+  (Argon2), key exchange (X25519), signatures (EdDSA with BLAKE2b, and
+  Ed25519 proper) and Elligator 2 hidden key encoding.
+endef
+
+MAKE_FLAGS += \
+	PREFIX=/usr
+
+# The stock "install" target also runs install-doc, which drags in the man
+# pages we do not ship on the target.
+define Build/Install
+	$(call Build/Install/Default,install-lib install-pc)
+endef
+
+define Build/InstallDev
+	$(INSTALL_DIR) $(1)/usr/include
+	$(CP) $(PKG_INSTALL_DIR)/usr/include/monocypher.h $(1)/usr/include/
+	$(CP) $(PKG_INSTALL_DIR)/usr/include/monocypher-ed25519.h $(1)/usr/include/
+	$(INSTALL_DIR) $(1)/usr/lib
+	$(CP) $(PKG_INSTALL_DIR)/usr/lib/libmonocypher.so* $(1)/usr/lib/
+	$(INSTALL_DIR) $(1)/usr/lib/pkgconfig
+	$(CP) $(PKG_INSTALL_DIR)/usr/lib/pkgconfig/monocypher.pc $(1)/usr/lib/pkgconfig/
+endef
+
+define Package/libmonocypher/install
+	$(INSTALL_DIR) $(1)/usr/lib
+	$(CP) $(PKG_INSTALL_DIR)/usr/lib/libmonocypher.so.* $(1)/usr/lib/
+endef
+
+$(eval $(call BuildPackage,libmonocypher))