Add frei0r

Apparently, the code for this in ffmpeg is ancient, and does not use the
built in dlfcn compat code, so... adding the wrapper it is.

scripts.d/50-dlfcn-win32.sh

@@ -0,0 +1,21 @@
+#!/bin/bash
+
+DLFCN_WIN32_REPO="https://github.com/dlfcn-win32/dlfcn-win32.git"
+DLFCN_WIN32_COMMIT="010969070719fe14435f4b146ecef5e65df0098f"
+
+ffbuild_enabled() {
+    [[ $TARGET != win* ]] && return -1
+    return 0
+}
+
+ffbuild_dockerbuild() {
+    git-mini-clone "$DLFCN_WIN32_REPO" "$DLFCN_WIN32_COMMIT" dlfcn-win32
+    cd dlfcn-win32
+
+    mkdir build && cd build
+
+    cmake -DCMAKE_TOOLCHAIN_FILE="$FFBUILD_CMAKE_TOOLCHAIN" -DCMAKE_BUILD_TYPE=Release -DCMAKE_INSTALL_PREFIX="$FFBUILD_PREFIX" \
+        -DBUILD_SHARED_LIBS=OFF -DBUILD_TESTS=OFF ..
+    make -j$(nproc)
+    make install
+}

scripts.d/50-frei0r.sh

@@ -0,0 +1,46 @@
+#!/bin/bash
+
+FREI0R_REPO="https://github.com/dyne/frei0r.git"
+FREI0R_COMMIT="86475d3e11e1061bf161e6ed3830fe2cf3d172ac"
+
+ffbuild_enabled() {
+    [[ $VARIANT == lgpl* ]] && return -1
+    return 0
+}
+
+ffbuild_dockerbuild() {
+    git-mini-clone "$FREI0R_REPO" "$FREI0R_COMMIT" frei0r
+    cd frei0r
+
+    ./autogen.sh
+
+    local myconf=(
+        --prefix="$FFBUILD_PREFIX"
+        --disable-shared
+        --enable-static
+        --with-pic
+        --enable-cpuflags
+    )
+
+    if [[ $TARGET == win* || $TARGET == linux* ]]; then
+        myconf+=(
+            --host="$FFBUILD_TOOLCHAIN"
+        )
+    else
+        echo "Unknown target"
+        return -1
+    fi
+
+    ./configure "${myconf[@]}"
+    make -C include -j$(nproc)
+    make -C include install
+    make install-pkgconfigDATA
+}
+
+ffbuild_configure() {
+    echo --enable-frei0r
+}
+
+ffbuild_unconfigure() {
+    echo --disable-frei0r
+}