deps: make libc optional

libc dependency is only use by the lianad
binary it is not needed for liana-gui.
This commit makes the dependency optional
by introducing a new default feature named
daemon.

liana/src/daemonize.rs is still compiling
because the feature daemon is marked as required
for the lianad binary.

Cargo.toml

@@ -12,7 +12,7 @@ exclude = [".github/", ".cirrus.yml", "tests/",  "test_data/", "contrib/", "pypr
 [[bin]]
 name = "lianad"
 path = "src/bin/daemon.rs"
-required-features = ["jsonrpc_server"]
+required-features = ["jsonrpc_server", "daemon"]
 
 [[bin]]
 name = "liana-cli"
@@ -20,8 +20,9 @@ path = "src/bin/cli.rs"
 required-features = ["jsonrpc_server"]
 
 [features]
-default = ["jsonrpc_server"]
+default = ["jsonrpc_server", "daemon"]
 jsonrpc_server = []
+daemon = ["libc"]
 
 [dependencies]
 # For managing transactions (it re-exports the bitcoin crate)
@@ -52,7 +53,7 @@ rusqlite = { version = "0.26.3", features = ["bundled", "unlock_notify"] }
 jsonrpc = "0.12"
 
 # Used for daemonization
-libc = "0.2"
+libc = { version = "0.2", optional = true }
 
 # Used for PSBTs
 base64 = "0.13"

src/lib.rs

@@ -1,7 +1,7 @@
 mod bitcoin;
 pub mod commands;
 pub mod config;
-#[cfg(unix)]
+#[cfg(all(unix, feature = "daemon"))]
 mod daemonize;
 mod database;
 pub mod descriptors;
@@ -381,7 +381,7 @@ impl DaemonHandle {
         // If we are on a UNIX system and they told us to daemonize, do it now.
         // NOTE: it's safe to daemonize now, as we don't carry any open DB connection
         // https://www.sqlite.org/howtocorrupt.html#_carrying_an_open_database_connection_across_a_fork_
-        #[cfg(unix)]
+        #[cfg(all(unix, feature = "daemon"))]
         if config.daemon {
             log::info!("Daemonizing");
             let log_file = data_dir.as_path().join("log");