Add zlib and its build scripts

.gitmodules

@@ -31,3 +31,6 @@
 [submodule "third_party/aom"]
 	path = third_party/aom
 	url = https://github.com/ffmpegwasm/aom
+[submodule "third_party/zlib"]
+	path = third_party/zlib
+	url = https://github.com/ffmpegwasm/zlib

build.sh

@@ -8,6 +8,8 @@ SCRIPT_ROOT=$(dirname $0)/wasm/build-scripts
 emcc -v
 # install dependencies
 $SCRIPT_ROOT/install-deps.sh
+# build zlib
+$SCRIPT_ROOT/build-zlib.sh
 # build x264
 $SCRIPT_ROOT/build-x264.sh
 # build x265

zlib @ cacf7f1d

+Subproject commit cacf7f1d4e3d44d871b605da3b647f07d718623f

wasm/build-scripts/build-ffmpeg.sh

@@ -9,7 +9,7 @@ FLAGS=(
   -I. -I./fftools -I$BUILD_DIR/include
   -Llibavcodec -Llibavdevice -Llibavfilter -Llibavformat -Llibavresample -Llibavutil -Llibpostproc -Llibswscale -Llibswresample -L$BUILD_DIR/lib
   -Wno-deprecated-declarations -Wno-pointer-sign -Wno-implicit-int-float-conversion -Wno-switch -Wno-parentheses -Qunused-arguments
-  -lavdevice -lavfilter -lavformat -lavcodec -lswresample -lswscale -lavutil -lpostproc -lm -lx264 -lx265 -lvpx -lwavpack -lmp3lame -lfdk-aac -lvorbis -lvorbisenc -lvorbisfile -logg -ltheora -ltheoraenc -ltheoradec -pthread
+  -lavdevice -lavfilter -lavformat -lavcodec -lswresample -lswscale -lavutil -lpostproc -lm -lx264 -lx265 -lvpx -lwavpack -lmp3lame -lfdk-aac -lvorbis -lvorbisenc -lvorbisfile -logg -ltheora -ltheoraenc -ltheoradec -lz -pthread
   fftools/ffmpeg_opt.c fftools/ffmpeg_filter.c fftools/ffmpeg_hw.c fftools/cmdutils.c fftools/ffmpeg.c
   -o wasm/dist/ffmpeg-core.js
   -s USE_SDL=2                                  # use SDL2

wasm/build-scripts/build-zlib.sh

+#!/bin/bash
+
+set -euo pipefail
+source $(dirname $0)/var.sh
+
+LIB_PATH=third_party/zlib
+CXXFLAGS="-s USE_PTHREADS=1 $OPTIM_FLAGS"
+CM_FLAGS=(
+  -DCMAKE_INSTALL_PREFIX=$BUILD_DIR
+  -DCMAKE_TOOLCHAIN_FILE=$TOOLCHAIN_FILE
+  -DBUILD_SHARED_LIBS=OFF
+)
+echo "CM_FLAGS=${CONF_FLAGS[@]}"
+
+cd $LIB_PATH
+rm -rf build zconf.h
+mkdir -p build
+cd build
+emmake cmake .. -DCMAKE_C_FLAGS="$CXXFLAGS" ${CM_FLAGS[@]}
+emmake make clean
+emmake make install
+cd $ROOT_DIR

wasm/build-scripts/configure-ffmpeg.sh

@@ -7,6 +7,7 @@ FLAGS=(
   "${FFMPEG_CONFIG_FLAGS_BASE[@]}"
   --enable-gpl            # required by x264
   --enable-nonfree        # required by fdk-aac
+  --enable-zlib           # enable zlib
   --enable-libx264        # enable x264
   --enable-libx265        # enable x265
   --enable-libvpx         # enable libvpx / webm