exclude sys for doc build (#31)

Author: rex-schilasky

rustecal-core/Cargo.toml

@@ -1,9 +1,9 @@
 [package]
 name = "rustecal-core"
-version = "0.1.1"
+version = "0.1.2"
 authors = ["Rex Schilasky"]
 edition = "2021"
-description = "Idiomatic Rust API for Eclipse eCAL - Core Functionality"
+description = "Core API for Eclipse eCAL"
 license = "Apache-2.0"
 repository = "https://github.com/eclipse-ecal/rustecal"
 documentation = "https://docs.rs/rustecal-core"
@@ -12,10 +12,17 @@ keywords = ["ecal", "ipc", "pubsub", "server-client", "middleware"]
 categories = ["network-programming", "api-bindings"]
 
 [dependencies]
-rustecal-sys = { version = "0.1.0", path = "../rustecal-sys" }
+rustecal-sys = { version = "0.1.0", path = "../rustecal-sys", optional = true }
 once_cell     = "1.17"
 thiserror     = "1.0"
 bitflags      = "1.3"
 
 [features]
-default = []
+# Include sys bindings by default in local builds
+default = ["sys"]
+# Optional feature to enable the rustecal-sys dependency
+sys     = ["rustecal-sys"]
+
+[package.metadata.docs.rs]
+default-features = false
+features = []