Add copy of opus library in deps/third_party.

opus/Makefile.unix

+#################### COMPILE OPTIONS #######################
+
+# Uncomment this for fixed-point build
+#FIXED_POINT=1
+
+# It is strongly recommended to uncomment one of these
+# VAR_ARRAYS: Use C99 variable-length arrays for stack allocation
+# USE_ALLOCA: Use alloca() for stack allocation
+# If none is defined, then the fallback is a non-threadsafe global array
+CFLAGS := -DUSE_ALLOCA $(CFLAGS)
+#CFLAGS := -DVAR_ARRAYS $(CFLAGS)
+
+# These options affect performance
+# HAVE_LRINTF: Use C99 intrinsics to speed up float-to-int conversion
+#      inline: Don't use the 'inline' keyword (for ANSI C compilers)
+#    restrict: Don't use the 'restrict' keyword (for pre-C99 compilers)
+#CFLAGS := -DHAVE_LRINTF $(CFLAGS)
+#CFLAGS := -Dinline= $(CFLAGS)
+CFLAGS := -Drestrict= $(CFLAGS)
+
+###################### END OF OPTIONS ######################
+
+include version.mk
+CFLAGS += -DOPUS_VERSION='$(OPUS_VERSION)'
+include silk_sources.mk
+include celt_sources.mk
+include opus_sources.mk
+
+ifdef FIXED_POINT
+SILK_SOURCES += $(SILK_SOURCES_FIXED)
+else
+SILK_SOURCES += $(SILK_SOURCES_FLOAT)
+endif
+
+EXESUFFIX =
+LIBPREFIX = lib
+LIBSUFFIX = .a
+OBJSUFFIX = .o
+
+CC     = $(TOOLCHAIN_PREFIX)cc$(TOOLCHAIN_SUFFIX)
+AR     = $(TOOLCHAIN_PREFIX)ar
+RANLIB = $(TOOLCHAIN_PREFIX)ranlib
+CP     = $(TOOLCHAIN_PREFIX)cp
+
+cppflags-from-defines   = $(addprefix -D,$(1))
+cppflags-from-includes  = $(addprefix -I,$(1))
+ldflags-from-ldlibdirs  = $(addprefix -L,$(1))
+ldlibs-from-libs                = $(addprefix -l,$(1))
+
+WARNINGS = -Wall -W -Wstrict-prototypes -Wextra -Wcast-align -Wnested-externs -Wshadow
+CFLAGS  += -O2 -g $(WARNINGS) -DOPUS_BUILD
+ifdef FIXED_POINT
+CFLAGS += -DFIXED_POINT=1 -DDISABLE_FLOAT_API
+endif
+
+CINCLUDES += include/ \
+        silk/ \
+        silk/float/ \
+        silk/fixed/ \
+        celt/ \
+        src/
+
+# VPATH e.g. VPATH = src:../headers
+VPATH = ./ \
+        silk/interface \
+        silk/src_FIX \
+        silk/src_FLP \
+        silk/src_SigProc_FIX \
+        silk/src_SigProc_FLP \
+        test
+
+LIBS = m
+
+LDLIBDIRS = ./
+
+CFLAGS  += $(call cppflags-from-defines,$(CDEFINES))
+CFLAGS  += $(call cppflags-from-includes,$(CINCLUDES))
+LDFLAGS += $(call ldflags-from-ldlibdirs,$(LDLIBDIRS))
+LDLIBS  += $(call ldlibs-from-libs,$(LIBS))
+
+COMPILE.c.cmdline   = $(CC) -c $(CFLAGS) -o $@ $<
+LINK.o              = $(CC) $(LDPREFLAGS) $(LDFLAGS)
+LINK.o.cmdline      = $(LINK.o) $^ $(LDLIBS) -o $@$(EXESUFFIX)
+
+ARCHIVE.cmdline     = $(AR) $(ARFLAGS) $@ $^ && $(RANLIB) $@
+
+%$(OBJSUFFIX):%.c
+        $(COMPILE.c.cmdline)
+
+%$(OBJSUFFIX):%.cpp
+        $(COMPILE.cpp.cmdline)
+
+# Directives
+
+
+# Variable definitions
+LIB_NAME = opus
+TARGET = $(LIBPREFIX)$(LIB_NAME)$(LIBSUFFIX)
+
+SRCS_C = $(SILK_SOURCES) $(CELT_SOURCES) $(OPUS_SOURCES)
+
+OBJS := $(patsubst %.c,%$(OBJSUFFIX),$(SRCS_C))
+
+OPUSDEMO_SRCS_C = src/opus_demo.c
+OPUSDEMO_OBJS := $(patsubst %.c,%$(OBJSUFFIX),$(OPUSDEMO_SRCS_C))
+
+OPUSCOMPARE_SRCS_C = src/opus_compare.c
+OPUSCOMPARE_OBJS := $(patsubst %.c,%$(OBJSUFFIX),$(OPUSCOMPARE_SRCS_C))
+
+# Rules
+default: all
+
+all: $(TARGET) lib opus_demo opus_compare
+
+lib: $(TARGET)
+
+$(TARGET): $(OBJS)
+        $(ARCHIVE.cmdline)
+
+opus_demo$(EXESUFFIX): $(OPUSDEMO_OBJS) $(TARGET)
+        $(LINK.o.cmdline)
+
+opus_compare$(EXESUFFIX): $(OPUSCOMPARE_OBJS)
+        $(LINK.o.cmdline)
+
+clean:
+        rm -f opus_demo$(EXESUFFIX) opus_compare$(EXESUFFIX) $(TARGET) $(OBJS) $(OPUSDEMO_OBJS)