a WebP encoder

converts PNG & JPEG to WebP

This is an experimental early version, with lot of room
of later optimizations in both speed and quality.

Compile with the usual `./configure && make`
Command line example is examples/cwebp

Usage:

   cwebp [options] -q quality input.png -o output.webp

where 'quality' is between 0 (poor) to 100 (very good).
Typical value is around 80.

More encoding options with 'cwebp -longhelp'

Change-Id: I577a94f6f622a0c44bdfa9daf1086ace89d45539

src/enc/Makefile.am

@@ -0,0 +1,15 @@
+AM_CPPFLAGS = -I$(top_builddir)/src
+
+libwebpencode_la_SOURCES = analysis.c bit_writer.c bit_writer.h \
+                          config.c cost.c cost.h dsp.c filter.c \
+                          frame.c iterator.c picture.c quant.c  \
+                          syntax.c tree.c vp8enci.h webpenc.c
+libwebpencode_la_LDFLAGS = -version-info 0:0:0 -lm
+libwebpencodeinclude_HEADERS = ../webp/encode.h ../webp/types.h
+libwebpencodeincludedir = $(includedir)/webp
+
+noinst_HEADERS = cost.h bit_writer.h vp8enci.h
+noinst_LTLIBRARIES = libwebpencode.la
+# uncomment the following line (and comment the above) if you want
+# to install libwebpencode library.
+#lib_LTLIBRARIES = libwebpencode.la