Fix cross-compilation by deriving target multiarch from Cargo target triple #701
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When PKG_CONFIG_SYSROOT_DIR is set (cross-compilation scenario), check for OpenCV headers under the sysroot directory first before falling back to host system paths. Co-authored-by: twistedfall <406037+twistedfall@users.noreply.github.com>
When cross-compiling, detect the target's multiarch from CARGO_CFG_TARGET_* environment variables instead of querying the build host. This ensures we look for OpenCV headers in the correct multiarch directory for the target platform. Co-authored-by: twistedfall <406037+twistedfall@users.noreply.github.com>
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[WIP] Fix broken build in example Dockerfile for cross compiling
Fix cross-compilation by deriving target multiarch from Cargo target triple
Nov 18, 2025
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twistedfall
November 18, 2025 15:59
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Fixes #689
Cross-compilation with
PKG_CONFIG_SYSROOT_DIRfails when probing OpenCV because multiarch detection queries the build host instead of the target, causing header lookups in wrong paths.Changes
Modified
build/header.rs::get_multiarch_header_dir():Derive target multiarch from
CARGO_CFG_TARGET_*instead of querying build hostx86_64-*-linux-gnu→x86_64-linux-gnu,aarch64-*-linux-gnu→aarch64-linux-gnu, etc.Prepend
PKG_CONFIG_SYSROOT_DIRto multiarch paths when set{sysroot}/usr/include/{multiarch}/opencv4before/usr/include/{multiarch}/opencv4Add debug logging to show which multiarch and paths are being checked
Example
Cross-compiling for aarch64 from x86_64 host:
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