docker: Self-build fontforge

[why]
The most recent fontforge release version fixes one issue, but introduces
a new one. While the issue has been fixed there is still no new release.

[how]
Build fontforge from scratch from a specific commit that is known to be
good.

Fixes #1772
Fixes #1948

Signed-off-by: Fini Jastrow <ulf.fini.jastrow@desy.de>

Dockerfile

@@ -6,7 +6,63 @@ LABEL org.opencontainers.image.title="Nerd Fonts Patcher" \
       org.opencontainers.image.source="https://github.com/ryanoasis/nerd-fonts" \
       org.opencontainers.image.licenses="MIT"
 
-RUN apk update && apk upgrade && apk add --no-cache fontforge parallel --repository=https://dl-cdn.alpinelinux.org/alpine/latest-stable/community
+RUN <<ENDOFRUN
+apk update
+apk upgrade
+echo "Add build dependencies"
+apk add --no-cache --repository=https://dl-cdn.alpinelinux.org/alpine/latest-stable/community \
+  alpine-sdk \
+  cmake \
+  coreutils \
+  freetype-dev \
+  gettext-dev \
+  harfbuzz-dev \
+  libxml2-dev \
+  ninja \
+  python3-dev \
+  woff2-dev
+echo "Add execute dependencies"
+apk add --no-cache --repository=https://dl-cdn.alpinelinux.org/alpine/latest-stable/community \
+  freetype \
+  harfbuzz \
+  libxml2 \
+  python3 \
+  woff2
+echo "Fetch and build fontforge"
+git clone https://github.com/fontforge/fontforge.git
+cd fontforge
+git checkout 3a960a4d83c65b8ff5fc0bab8b1f19964aa023df
+mkdir build
+cd build
+cmake -GNinja \
+  -DENABLE_GUI=off \
+  -DENABLE_DOCS=off \
+  -DENABLE_NATIVE_SCRIPTING=off \
+  -DENABLE_LIBSPIRO=off \
+  -DENABLE_PYTHON_EXTENSION=off \
+  ..
+ninja
+cmake --install . --strip
+cd ../..
+rm -rf fontforge
+rm -rf /usr/local/share
+echo "Remove build dependencies"
+apk del --rdepends \
+  alpine-sdk \
+  cmake \
+  coreutils \
+  freetype-dev \
+  gettext-dev \
+  harfbuzz-dev \
+  libxml2-dev \
+  ninja \
+  python3-dev \
+  tiff-dev \
+  woff2-dev
+echo "Add additional runtime dependencies"
+apk add --no-cache --repository=https://dl-cdn.alpinelinux.org/alpine/latest-stable/community \
+  parallel
+ENDOFRUN
 
 ENV PYTHONIOENCODING=utf-8