Prepare build of private spandsp version to avoid conflicts with incompatible versions installed by other means

[MayamaTakeshi]

Then we should statically link to it.

[MayamaTakeshi]

Here is the current situation:

takeshi:sip-lab$ ldd build/Release/addon.node linux-vdso.so.1 (0x00007ffd519b9000) libstdc++.so.6 => /usr/lib/x86_64-linux-gnu/libstdc++.so.6 (0x00007effef429000) libssl.so.1.1 => /usr/lib/x86_64-linux-gnu/libssl.so.1.1 (0x00007effef396000) libcrypto.so.1.1 => /usr/lib/x86_64-linux-gnu/libcrypto.so.1.1 (0x00007effef0c0000) libuuid.so.1 => /lib/x86_64-linux-gnu/libuuid.so.1 (0x00007effef0b7000) libspandsp.so.2 => /usr/lib/x86_64-linux-gnu/libspandsp.so.2 (0x00007effeeff2000) libpcap.so.0.8 => /usr/lib/x86_64-linux-gnu/libpcap.so.0.8 (0x00007effeefa7000) libpthread.so.0 => /lib/x86_64-linux-gnu/libpthread.so.0 (0x00007effeef82000) libspeex.so.1 => /usr/lib/x86_64-linux-gnu/libspeex.so.1 (0x00007effeef64000) libbcg729.so.0 => /usr/local/lib/libbcg729.so.0 (0x00007effeef4d000) libm.so.6 => /lib/x86_64-linux-gnu/libm.so.6 (0x00007effeedfe000) libgcc_s.so.1 => /lib/x86_64-linux-gnu/libgcc_s.so.1 (0x00007effeede3000) libc.so.6 => /lib/x86_64-linux-gnu/libc.so.6 (0x00007effeebf1000) /lib64/ld-linux-x86-64.so.2 (0x00007effef76d000) libdl.so.2 => /lib/x86_64-linux-gnu/libdl.so.2 (0x00007effeebe9000) libtiff.so.5 => /usr/lib/x86_64-linux-gnu/libtiff.so.5 (0x00007effeeb68000) libwebp.so.6 => /usr/lib/x86_64-linux-gnu/libwebp.so.6 (0x00007effeeafe000) libzstd.so.1 => /usr/lib/x86_64-linux-gnu/libzstd.so.1 (0x00007effeea55000) liblzma.so.5 => /lib/x86_64-linux-gnu/liblzma.so.5 (0x00007effeea2c000) libjbig.so.0 => /usr/lib/x86_64-linux-gnu/libjbig.so.0 (0x00007effee81c000) libjpeg.so.8 => /usr/lib/x86_64-linux-gnu/libjpeg.so.8 (0x00007effee797000) libz.so.1 => /lib/x86_64-linux-gnu/libz.so.1 (0x00007effee77b000) takeshi:sip-lab$

[MayamaTakeshi]

Done. After changes:

takeshi:sip-lab$ ldd build/Release/addon.node linux-vdso.so.1 (0x00007ffcd1192000) libstdc++.so.6 => /usr/lib/x86_64-linux-gnu/libstdc++.so.6 (0x00007f5ca43d7000) libssl.so.1.1 => /usr/lib/x86_64-linux-gnu/libssl.so.1.1 (0x00007f5ca4344000) libcrypto.so.1.1 => /usr/lib/x86_64-linux-gnu/libcrypto.so.1.1 (0x00007f5ca406e000) libuuid.so.1 => /lib/x86_64-linux-gnu/libuuid.so.1 (0x00007f5ca4065000) libtiff.so.5 => /usr/lib/x86_64-linux-gnu/libtiff.so.5 (0x00007f5ca3fe4000) libpcap.so.0.8 => /usr/lib/x86_64-linux-gnu/libpcap.so.0.8 (0x00007f5ca3f99000) libpthread.so.0 => /lib/x86_64-linux-gnu/libpthread.so.0 (0x00007f5ca3f74000) libspeex.so.1 => /usr/lib/x86_64-linux-gnu/libspeex.so.1 (0x00007f5ca3f56000) libbcg729.so.0 => /usr/local/lib/libbcg729.so.0 (0x00007f5ca3f3f000) libm.so.6 => /lib/x86_64-linux-gnu/libm.so.6 (0x00007f5ca3df0000) libgcc_s.so.1 => /lib/x86_64-linux-gnu/libgcc_s.so.1 (0x00007f5ca3dd5000) libc.so.6 => /lib/x86_64-linux-gnu/libc.so.6 (0x00007f5ca3be3000) /lib64/ld-linux-x86-64.so.2 (0x00007f5ca47a3000) libdl.so.2 => /lib/x86_64-linux-gnu/libdl.so.2 (0x00007f5ca3bdb000) libwebp.so.6 => /usr/lib/x86_64-linux-gnu/libwebp.so.6 (0x00007f5ca3b71000) libzstd.so.1 => /usr/lib/x86_64-linux-gnu/libzstd.so.1 (0x00007f5ca3ac8000) liblzma.so.5 => /lib/x86_64-linux-gnu/liblzma.so.5 (0x00007f5ca3a9f000) libjbig.so.0 => /usr/lib/x86_64-linux-gnu/libjbig.so.0 (0x00007f5ca3891000) libjpeg.so.8 => /usr/lib/x86_64-linux-gnu/libjpeg.so.8 (0x00007f5ca380c000) libz.so.1 => /lib/x86_64-linux-gnu/libz.so.1 (0x00007f5ca37ee000) takeshi:sip-lab$