lavfi: install asrc_abuffer.h header

The header is part of the public API, in particular is used by
doc/examples/filtering_audio.c.

doc/APIchanges

@@ -13,6 +13,9 @@ libavutil:   2011-04-18
 
 API changes, most recent first:
 
+2012-04-12 - xxxxxxx - lavfi 2.68.100
+  Install libavfilter/asrc_abuffer.h public header.
+
 2012-03-26 - a67d9cf - lavfi 2.66.100
   Add avfilter_fill_frame_from_{audio_,}buffer_ref() functions.
 

libavfilter/Makefile

@@ -12,7 +12,7 @@ FFLIBS-$(CONFIG_REMOVELOGO_FILTER)           += swscale avformat avcodec
 FFLIBS-$(CONFIG_SCALE_FILTER)                += swscale
 FFLIBS-$(CONFIG_MP_FILTER)                   += avcodec postproc
 
-HEADERS = avcodec.h avfilter.h avfiltergraph.h buffersink.h version.h vsrc_buffer.h
+HEADERS = asrc_abuffer.h avcodec.h avfilter.h avfiltergraph.h buffersink.h version.h vsrc_buffer.h
 
 OBJS = allfilters.o                                                     \
        avfilter.o                                                       \

libavfilter/version.h

@@ -29,8 +29,8 @@
 #include "libavutil/avutil.h"
 
 #define LIBAVFILTER_VERSION_MAJOR  2
-#define LIBAVFILTER_VERSION_MINOR 67
-#define LIBAVFILTER_VERSION_MICRO 101
+#define LIBAVFILTER_VERSION_MINOR 68
+#define LIBAVFILTER_VERSION_MICRO 100
 
 #define LIBAVFILTER_VERSION_INT AV_VERSION_INT(LIBAVFILTER_VERSION_MAJOR, \
                                                LIBAVFILTER_VERSION_MINOR, \