removed cargo channel parameter by default (#301)

CMakeLists.txt

@@ -27,7 +27,7 @@ declare_cache_var_true_if_vscode(ZENOHC_BUILD_IN_SOURCE_TREE "Do build inside so
 declare_cache_var(ZENOHC_BUILD_WITH_LOGGER_AUTOINIT TRUE BOOL "Enable logger-autoinit zenoh-c feature")
 declare_cache_var(ZENOHC_BUILD_WITH_SHARED_MEMORY TRUE BOOL "Enable shared-memory zenoh-c feature")
 declare_cache_var(ZENOHC_CUSTOM_TARGET "" STRING "Rust target for cross compilation, 'aarch64-unknown-linux-gnu' for example")
-declare_cache_var(ZENOHC_CARGO_CHANNEL "stable" STRING "Cargo channel selected: stable or nightly")
+declare_cache_var(ZENOHC_CARGO_CHANNEL "" STRING "Cargo channel parameter. Should be '+stable', '+nightly' or empty value")
 declare_cache_var(ZENOHC_CARGO_FLAGS "" STRING "Additional cargo flags")
 declare_cache_var(ZENOHC_LIB_STATIC FALSE BOOL "Alias zenohc::lib target to zenohc::static if TRUE, to zenohc::shared if FALSE")
 
@@ -198,8 +198,8 @@ file(GLOB_RECURSE rust_sources "Cargo.toml.in" "src/*.rs" "build.rs" "splitguide
 add_custom_command(
 	OUTPUT ${libs}
 	COMMAND ${CMAKE_COMMAND} -E echo \"RUSTFLAGS = $$RUSTFLAGS\"
-	COMMAND ${CMAKE_COMMAND} -E echo \"cargo +${ZENOHC_CARGO_CHANNEL} build ${cargo_flags}\"
-	COMMAND cargo +${ZENOHC_CARGO_CHANNEL} build ${cargo_flags}
+	COMMAND ${CMAKE_COMMAND} -E echo \"cargo ${ZENOHC_CARGO_CHANNEL} build ${cargo_flags}\"
+	COMMAND cargo ${ZENOHC_CARGO_CHANNEL} build ${cargo_flags}
 	VERBATIM
 	COMMAND_EXPAND_LISTS
 	DEPENDS "${rust_sources}"