TEMP: dynamically link against liblz4 for testing

Signed-off-by: Wolfgang Bumiller <w.bumiller@proxmox.com>

Cargo.toml

@@ -43,3 +43,6 @@ pam-sys = "0.5"
 pam = "0.7"
 lz4 = "1.23"
 xdg = "2.2"
+
+[patch.crates-io]
+lz4-sys = { path = "lz4-rs/lz4-sys" }

Makefile

@@ -46,10 +46,10 @@ all: cargo-build $(SUBDIRS)
 $(SUBDIRS):
 	$(MAKE) -C $@
 
-test:
+test: | dependencies
 	cargo test $(CARGO_BUILD_ARGS)
 
-doc:
+doc: | dependencies
 	cargo doc --no-deps $(CARGO_BUILD_ARGS)
 
 # always re-create this dir
@@ -93,7 +93,7 @@ dinstall: ${DEB}
 docs: cargo-build
 
 .PHONY: cargo-build
-cargo-build:
+cargo-build: | dependencies
 	cargo build $(CARGO_BUILD_ARGS)
 
 $(COMPILED_BINS): cargo-build
@@ -110,3 +110,17 @@ install: $(COMPILED_BINS)
 	    install -m755 $(COMPILEDIR)/$(i) $(DESTDIR)$(LIBEXECDIR)/proxmox-backup/ ;)
 	$(MAKE) -C www install
 	$(MAKE) -C docs install
+
+#
+# External dependency patching:
+#
+
+dependencies: lz4-rs
+
+# We want to dynamically link against the system's liblz4!
+# The lz4-sys crate provides some more helpers in addition to the 'extern "C"' block so we still
+# need to use its rust code directly in order for the `lz4` crate to be happy.
+lz4-rs:
+	git clone https://github.com/bozaro/lz4-rs
+	echo 'fn main() { println!("cargo:rustc-link-lib=lz4"); }' \
+		>lz4-rs/lz4-sys/build.rs