build/macos: support osxcross docker container

README.md

@@ -232,6 +232,20 @@ go build -ldflags '-s -w'
 
 Installing `qt@5` from [Homebrew](https://brew.sh/) may be very slow if Homebrew chooses to do a from-source build instead of a binary Bottle build, particularly owing to QtWebEngine (Chromium).
 
+### macOS (Docker)
+
+*Tested with osxcross 14.5 / Go 1.19 / MacPorts Qt 5.15 / Debian Clang 14.0*
+
+For dynamic linking:
+
+1. Build the necessary docker container for cross-compilation:
+	- `docker build -t miqt/osxcross:latest -f docker/macos-cross-x86_64-sdk14.5-go1.19-qt5.15-dynamic.Dockerfile .`
+2. Build your application:
+	- `docker run --rm -v $(pwd):/src -w /src miqt/osxcross:latest go build -ldflags '-s -w'`
+3. Copy necessary Qt LGPL libraries and plugin files.
+
+See FAQ Q3 for advice about docker performance.
+
 ### Android (Docker)
 
 *Tested with Raymii Qt 5.15 / Android SDK 31 / Android NDK 22*

docker/macos-cross-x86_64-sdk14.5-go1.19-qt5.15-dynamic.Dockerfile

@@ -0,0 +1,47 @@
+FROM crazymax/osxcross:14.5-debian AS osxcross
+
+FROM debian:bookworm
+
+COPY --from=osxcross /osxcross /osxcross
+
+RUN DEBIAN_FRONTEND=noninteractive apt-get update && \
+	apt-get install --no-install-recommends -qyy \
+		golang-go \
+		clang \
+		lld \
+		libc6-dev \
+		openssl \
+		bzip2 \
+		ca-certificates \
+		curl \
+		pkg-config && \
+    apt-get clean
+
+ENV PATH="/osxcross/bin:$PATH"
+ENV LD_LIBRARY_PATH="/osxcross/lib:$LD_LIBRARY_PATH"
+
+# The oldest macOS target with a working Qt 5.15 build on macports.org is High
+# Sierra (10.13)
+# @ref https://ports.macports.org/port/qt5-qtbase/details/
+#
+# Go 1.19 and Go 1.20 are the last versions of Go that can target macOS 10.13.
+# For later versions of Go, a higher MACOSX_DEPLOYMENT_TARGET version can be set.
+# @ref https://tip.golang.org/doc/go1.20#darwin
+ENV MACOSX_DEPLOYMENT_TARGET=10.13
+
+# Preemptively mark some dependencies as installed that don't seem to download properly
+RUN /usr/bin/env UNATTENDED=1 osxcross-macports fake-install py312 py312-packaging xorg xrender
+
+# Install Qt 5.15 and dependencies
+RUN /usr/bin/env UNATTENDED=1 osxcross-macports install qt5-qtbase
+
+RUN rmdir /opt/ && \
+	ln -s /osxcross/macports/pkgs/opt /opt
+
+ENV CC=x86_64-apple-darwin23.6-clang
+ENV CXX=x86_64-apple-darwin23.6-clang++
+ENV GOOS=darwin
+ENV GOARCH=amd64
+ENV CGO_ENABLED=1
+ENV PKG_CONFIG_PATH=/opt/local/libexec/qt5/lib/pkgconfig/
+ENV CGO_CXXFLAGS="-Wno-ignored-attributes -D_Bool=bool"