Include pkgconfig-native in cargo dependencies

pkg-config is used quite often by Rust libraries that link to native
system libraries, so add it as a build dependency to avoid confusing
errors. This doesn't add anything extra to the generated target image -
only the native version of pkg-config is installed.

Signed-off-by: Nick Stevens <[email protected]>

Author: nastevens

classes/cargo.bbclass

@@ -1,6 +1,11 @@
 inherit rust-common
 
-DEPENDS += "cargo-bin-cross-${TARGET_ARCH}"
+# Many crates rely on pkg-config to find native versions of their libraries for
+# linking - do the simple thing and make it generally available.
+DEPENDS_append = "\
+    cargo-bin-cross-${TARGET_ARCH} \
+    pkgconfig-native \
+"
 
 # Move CARGO_HOME from default of ~/.cargo
 export CARGO_HOME = "${WORKDIR}/cargo_home"