Ports: Add a bdwgc (aka libgc) port

For all your ports' garbage collection needs :^)

Ports/bdwgc/package.sh

@@ -0,0 +1,25 @@
+#!/usr/bin/env -S bash ../.port_include.sh
+
+port=bdwgc
+version=8.0.6
+use_fresh_config_sub=true
+files="https://github.com/ivmai/bdwgc/releases/download/v$version/gc-$version.tar.gz bdwgc.tar.gz 3b4914abc9fa76593596773e4da671d7ed4d5390e3d46fbf2e5f155e121bea11"
+depends=(libatomic_ops)
+workdir=gc-$version
+auth_type=sha256
+
+build() {
+    cd $workdir
+    mkdir build || true
+    cd build
+    cmake .. \
+        -Denable_threads=ON \
+        -DCMAKE_RUNTIME_OUTPUT_DIRECTORY="$DESTDIR/usr/local/bin" \
+        -DCMAKE_LIBRARY_OUTPUT_DIRECTORY="$DESTDIR/usr/local/lib"
+    cmake --build .
+}
+
+install() {
+    cd ..
+    cp -r include "$DESTDIR/usr/local/include/gc"
+}