Compilation stuff

./configure
....
checking lex library... -lfl
checking whether yytext is a pointer... yes
checking for bison... bison -y
checking for pkg-config... yes
checking for pkg-config... /usr/bin/pkg-config
checking pkg-config is at least version 0.9.0... yes
checking for LIBNFNETLINK... no
configure: error: Cannot find libnfnetlink >= 1.0.0

However libnfnetlink was installed.

# ls /usr/local/lib/pkgconfig/
libnetfilter_conntrack.pc libnfnetlink.pc

# pkg-config --libs libnfnetlink
Package libnfnetlink was not found in the pkg-config search path.
Perhaps you should add the directory containing `libnfnetlink.pc'
to the PKG_CONFIG_PATH environment variable
No package 'libnfnetlink' found


# PKG_CONFIG_PATH=/usr/local/lib/pkgconfig/ pkg-config --libs libnfnetlink
-L/usr/local/lib -lnfnetlink


Solution:
PKG_CONFIG_PATH=/usr/local/lib/pkgconfig/ ./configure