[PATCH v3] rust: respect CARGO_BUILD_TARGET when locating build output

[James Le Cuirot <chewi@gentoo.org>]

When cross-compiling, Cargo always writes to a target-tuple subdirectory
determined by CARGO_BUILD_TARGET, even when it matches the native tuple.
The build looked in $BUILD_DIR/$BUILD_TYPE directly, so it failed to
locate the freshly built library.

Respect CARGO_BUILD_TARGET in the output path so the correct artifact
is located.

Signed-off-by: James Le Cuirot <chewi@gentoo.org>
---

> This seems to be based on a bit stale codebase.  Specifically you
> would want to build on top of post-924dfced6b (Makefile: support
> universal macOS builds via RUST_TARGETS, 2026-07-08) version of
> Makefile.

Apologies, I had used the maint branch. Now rebased on master.

> When CARGO_BUILD_TARGET is not defined, this leaves double slashes
> in the resulting pathname, which may not be incorrect per-se, but
> still is not what you meant to say, which is probably a lot closer
> to
>
>     ${CARGO_BUILD_TARGET+$CARGO_BUILD_TARGET/}

I believed this would not cause an issue, so I intentionally went with
simplicity over correctness. It's not a big difference though, so this
revision goes with correctness.

 Makefile           | 2 +-
 src/cargo-meson.sh | 4 ++--
 2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/Makefile b/Makefile
index d4b7759..f0ca2e4 100644
--- a/Makefile
+++ b/Makefile
@@ -959,7 +959,7 @@ RUST_LIB_NAME = gitcore.lib
 else
 RUST_LIB_NAME = libgitcore.a
 endif
-RUST_LIB = target/$(RUST_BUILD_CONFIG)/$(RUST_LIB_NAME)
+RUST_LIB = target/$(if $(CARGO_BUILD_TARGET),$(CARGO_BUILD_TARGET)/)$(RUST_BUILD_CONFIG)/$(RUST_LIB_NAME)
 endif

 GITLIBS = common-main.o $(LIB_FILE)
diff --git a/src/cargo-meson.sh b/src/cargo-meson.sh
index 75f3cd1..83c7e7b 100755
--- a/src/cargo-meson.sh
+++ b/src/cargo-meson.sh
@@ -38,7 +38,7 @@ then
 	exit $RET
 fi

-if ! cmp "$BUILD_DIR/$BUILD_TYPE/$LIBNAME" "$BUILD_DIR/libgitcore.a" >/dev/null 2>&1
+if ! cmp "$BUILD_DIR/${CARGO_BUILD_TARGET:+$CARGO_BUILD_TARGET/}$BUILD_TYPE/$LIBNAME" "$BUILD_DIR/libgitcore.a" >/dev/null 2>&1
 then
-	cp "$BUILD_DIR/$BUILD_TYPE/$LIBNAME" "$BUILD_DIR/libgitcore.a"
+	cp "$BUILD_DIR/${CARGO_BUILD_TARGET:+$CARGO_BUILD_TARGET/}$BUILD_TYPE/$LIBNAME" "$BUILD_DIR/libgitcore.a"
 fi
--
2.55.0