These are redundant, the common AM_CPPFLAGS variable has it already.
Fixes: c96e0a17f3699 ("build: no recursive make for "examples/Makefile.am"")
Signed-off-by: Phil Sutter <phil@nwl.cc>
check_PROGRAMS += examples/nft-buffer
-examples_nft_buffer_AM_CPPFLAGS = -I$(srcdir)/include
examples_nft_buffer_LDADD = src/libnftables.la
check_PROGRAMS += examples/nft-json-file
-examples_nft_json_file_AM_CPPFLAGS = -I$(srcdir)/include
examples_nft_json_file_LDADD = src/libnftables.la
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