Android x86 : update ffmpeg & vpx src rules

This patch updates the ffmpeg and vpx contribs rules. It is necessary to
support the x86 architecture for Android and prevent Text Relocations in
the built libringjni.so

This patches uses code from VLC, please see :
https://github.com/videolan/vlc/commit/ac17dc8a

Change-Id: I4d55e1dc4b1436629e95676f2a76cdd61d3a2632
Tuleap: #508

contrib/src/ffmpeg/rules.mak

@@ -33,9 +33,11 @@ FFMPEGCONF += \
 		--enable-parser=vp8
 
 #librairies
+ifndef HAVE_ANDROID
 FFMPEGCONF += \
 		--enable-libx264 \
 		--enable-libvpx
+endif
 
 #encoders/decoders
 FFMPEGCONF += \
@@ -88,6 +90,18 @@ FFMPEGCONF += \
 
 DEPS_ffmpeg = iconv zlib x264 vpx opus speex $(DEPS_vpx)
 
+# Linux
+ifdef HAVE_LINUX
+FFMPEGCONF += --target-os=linux --enable-pic
+ifndef HAVE_ANDROID
+FFMPEGCONF += --enable-indev=v4l2 --enable-indev=x11grab --enable-x11grab
+else
+# used to avoid Text Relocations
+FFMPEGCONF += --extra-cxxflags=-fPIC --extra-cflags=-fPIC
+FFMPEGCONF += --disable-asm
+endif
+endif
+
 ifdef HAVE_CROSS_COMPILE
 FFMPEGCONF += --cross-prefix=$(HOST)-
 endif
@@ -101,6 +115,25 @@ ifeq ($(ARCH),x86_64)
 FFMPEGCONF += --arch=x86_64
 endif
 
+# ARM stuff
+ifeq ($(ARCH),arm)
+FFMPEGCONF += --arch=arm
+ifdef HAVE_NEON
+FFMPEGCONF += --enable-neon
+endif
+ifdef HAVE_ARMV7A
+FFMPEGCONF += --cpu=cortex-a8
+endif
+ifdef HAVE_ARMV6
+FFMPEGCONF += --cpu=armv6 --disable-neon
+endif
+endif
+
+# ARM64 stuff
+ifeq ($(ARCH),aarch64)
+FFMPEGCONF += --arch=aarch64
+endif
+
 # Windows
 ifdef HAVE_WIN32
 FFMPEGCONF += --target-os=mingw32 --enable-memalign-hack
@@ -128,6 +161,6 @@ ffmpeg: ffmpeg-$(FFMPEG_HASH).tar.xz .sum-ffmpeg
 .ffmpeg: ffmpeg
 	cd $< && $(HOSTVARS) ./configure \
 		--extra-ldflags="$(LDFLAGS)" $(FFMPEGCONF) \
-		--prefix="$(PREFIX)" --enable-static --disable-shared
+                --prefix="$(PREFIX)" --enable-static --disable-shared
 	cd $< && $(MAKE) install-libs install-headers
 	touch $@

contrib/src/vpx/rules.mak

@@ -97,16 +97,20 @@ endif
 ifdef HAVE_IOS
 VPX_CONF += --sdk-path=$(SDKROOT)
 endif
+LOCAL_HOSTVARS=
 ifdef HAVE_ANDROID
 # vpx configure.sh overrides our sysroot and it looks for it itself, and
 # uses that path to look for the compiler (which we already know)
 VPX_CONF += --sdk-path=$(shell dirname $(shell which $(CROSS_COMPILE)gcc))
 # needed for cpu-features.h
 VPX_CONF += --extra-cflags="-I $(ANDROID_NDK)/sources/cpufeatures/"
+# set an explicit alternative libc since the sysroot override can make it blank
+VPX_CONF += --libc=$(SYSROOT)
+LOCAL_HOSTVARS=$(HOSTVARS)
 endif
 
 .vpx: libvpx
-	cd $< && CROSS=$(VPX_CROSS) ./configure --target=$(VPX_TARGET) \
+	cd $< && CROSS=$(VPX_CROSS) $(LOCAL_HOSTVARS) ./configure --target=$(VPX_TARGET) \
 		$(VPX_CONF) --prefix=$(PREFIX)
 	cd $< && $(MAKE)
 	cd $< && ../../../contrib/src/pkg-static.sh vpx.pc