git clone git://anongit.freedesktop.org/gstreamer/gst-template.git && cd gst-template
cp -PR gst-plugin gst-plugin-foo && cd gst-plugin-foo/src
../tools/make_element Foo gstaudiofilter
nano Makefile.am # edit as necessary
cd .. && ./autogen.sh && make
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make  all-recursive
make[1]: Entering directory `/home/br/dev/cocktail/build/gst-template/gst-plugin-foo'
Making all in src
make[2]: Entering directory `/home/br/dev/cocktail/build/gst-template/gst-plugin-foo/src'
/bin/bash ../libtool  --tag=CC --tag=disable-static  --mode=compile gcc -DHAVE_CONFIG_H -I. -I..    -pthread -I/usr/include/gstreamer-1.0 -I/usr/include/glib-2.0 -I/usr/lib/x86_64-linux-gnu/glib-2.0/include   -Wall -g -O2 -Wall -MT libgstfoofilter_la-gstfoofilter.lo -MD -MP -MF .deps/libgstfoofilter_la-gstfoofilter.Tpo -c -o libgstfoofilter_la-gstfoofilter.lo `test -f 'gstfoofilter.c' || echo './'`gstfoofilter.c
libtool: compile:  gcc -DHAVE_CONFIG_H -I. -I.. -pthread -I/usr/include/gstreamer-1.0 -I/usr/include/glib-2.0 -I/usr/lib/x86_64-linux-gnu/glib-2.0/include -Wall -g -O2 -Wall -MT libgstfoofilter_la-gstfoofilter.lo -MD -MP -MF .deps/libgstfoofilter_la-gstfoofilter.Tpo -c gstfoofilter.c  -fPIC -DPIC -o .libs/libgstfoofilter_la-gstfoofilter.o
gstfoofilter.c:115:37: error: unknown type name 'gst_foo_filter'
gstfoofilter.c:116:21: error: expected declaration specifiers or '...' before '(' token
gstfoofilter.c:116:44: error: unknown type name 'DEBUG_INIT'
gstfoofilter.c:124:5: error: unknown type name 'GstRingBufferSpec'
gstfoofilter.c: In function 'gst_foo_filter_base_init':
gstfoofilter.c:149:32: error: 'GST_AUDIO_INT_STANDARD_PAD_TEMPLATE_CAPS' undeclared (first use in this function)
gstfoofilter.c:149:32: note: each undeclared identifier is reported only once for each function it appears in
gstfoofilter.c: In function 'gst_foo_filter_class_init':
gstfoofilter.c:176:31: error: 'gst_foo_filter_setup' undeclared (first use in this function)
gstfoofilter.c: In function 'gst_foo_filter_set_property':
gstfoofilter.c:197:3: warning: implicit declaration of function 'gst_foo_filter_get_type' [-Wimplicit-function-declaration]
gstfoofilter.c: At top level:
gstfoofilter.c:225:5: error: unknown type name 'GstRingBufferSpec'
gstfoofilter.c: In function 'gst_foo_filter_filter':
gstfoofilter.c:255:3: warning: implicit declaration of function 'GST_BUFFER_DATA' [-Wimplicit-function-declaration]
gstfoofilter.c:256:7: warning: implicit declaration of function 'GST_BUFFER_SIZE' [-Wimplicit-function-declaration]
gstfoofilter.c:256:7: warning: passing argument 1 of 'memcpy' makes pointer from integer without a cast [enabled by default]
/usr/include/x86_64-linux-gnu/bits/string3.h:49:1: note: expected 'void * __restrict__' but argument is of type 'int'
gstfoofilter.c:256:7: warning: passing argument 2 of 'memcpy' makes pointer from integer without a cast [enabled by default]
/usr/include/x86_64-linux-gnu/bits/string3.h:49:1: note: expected 'const void * __restrict__' but argument is of type 'int'
gstfoofilter.c:247:19: warning: variable 'audiofilter' set but not used [-Wunused-but-set-variable]
gstfoofilter.c:246:17: warning: variable 'foofilter_template' set but not used [-Wunused-but-set-variable]
gstfoofilter.c: In function 'gst_foo_filter_filter_inplace':
gstfoofilter.c:266:19: warning: variable 'audiofilter' set but not used [-Wunused-but-set-variable]
gstfoofilter.c:265:17: warning: variable 'foofilter_template' set but not used [-Wunused-but-set-variable]
gstfoofilter.c: At top level:
gstfoofilter.c:137:1: warning: 'gst_foo_filter_base_init' defined but not used [-Wunused-function]
gstfoofilter.c:155:1: warning: 'gst_foo_filter_class_init' defined but not used [-Wunused-function]
gstfoofilter.c:185:1: warning: 'gst_foo_filter_init' defined but not used [-Wunused-function]
make[2]: *** [libgstfoofilter_la-gstfoofilter.lo] Error 1
make[2]: Leaving directory `/home/br/dev/cocktail/build/gst-template/gst-plugin-foo/src'
make[1]: *** [all-recursive] Error 1
make[1]: Leaving directory `/home/br/dev/cocktail/build/gst-template/gst-plugin-foo'
make: *** [all] Error 2