[libass] Build with HarfBuzz (#4562)

This fixes the build that got broken when libass made HarfBuzz
a required dependency. This should also cover more libass code
with the fuzzing.

projects/libass/Dockerfile

@@ -15,9 +15,11 @@
 ################################################################################
 
 FROM gcr.io/oss-fuzz-base/base-builder
-RUN apt-get update && apt-get install -y make autoconf automake libtool pkg-config libfreetype6-dev libfontconfig1-dev
+RUN apt-get update && apt-get install -y make autoconf automake libtool pkg-config libfreetype6-dev libfontconfig1-dev python3-pip && \
+    pip3 install meson==0.53.0 ninja
 
 RUN git clone --depth 1 https://github.com/libass/libass.git
 RUN git clone --depth 1 https://github.com/behdad/fribidi.git
+RUN git clone --depth 1 https://github.com/harfbuzz/harfbuzz.git
 
 COPY build.sh libass_fuzzer.cc *.dict *.options $SRC/

projects/libass/build.sh

@@ -19,6 +19,24 @@ cd $SRC/fribidi
 ./autogen.sh --disable-docs --enable-static=yes --enable-shared=no --with-pic=yes --prefix=/work/
 make install
 
+cd $SRC/harfbuzz
+
+# setup
+build=$WORK/build
+
+# # cleanup
+rm -rf $build
+mkdir -p $build
+
+# disable sanitize=vptr for harfbuzz since it compiles without rtti
+CFLAGS="$CFLAGS -fno-sanitize=vptr" \
+CXXFLAGS="$CXXFLAGS -fno-sanitize=vptr" \
+meson --default-library=static --wrap-mode=nodownload \
+      -Dfuzzer_ldflags="$(echo $LIB_FUZZING_ENGINE)" \
+      --prefix=/work/ --libdir=lib $build \
+  || (cat build/meson-logs/meson-log.txt && false)
+meson install -C $build
+
 cd $SRC/libass
 
 export PKG_CONFIG_PATH=/work/lib/pkgconfig
@@ -29,7 +47,7 @@ make -j$(nproc)
 $CXX $CXXFLAGS -std=c++11 -I$SRC/libass -L/work/lib \
     $SRC/libass_fuzzer.cc -o $OUT/libass_fuzzer \
     $LIB_FUZZING_ENGINE libass/.libs/libass.a \
-    -Wl,-Bstatic -lfontconfig  -lfribidi -lfreetype -lz -lpng12 \
+    -Wl,-Bstatic -lfontconfig  -lfribidi -lfreetype -lharfbuzz -lz -lpng12 \
     -lexpat -Wl,-Bdynamic
 
 cp $SRC/*.dict $SRC/*.options $OUT/