Add ability to disable static library build

[randombit]

Fixes #1230 #1237 #1300

With the inclusion of a simple conditional statement in the template language it's become clear it's possible to eliminate the nmake vs Unix make distinction. I'll do that in a later PR.

[codecov-io]

Codecov Report

Merging #1324 into master will increase coverage by 0.41%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master    #1324      +/-   ##
==========================================
+ Coverage   91.87%   92.29%   +0.41%     
==========================================
  Files         466      466              
  Lines       43109    43109              
  Branches     5235     5235              
==========================================
+ Hits        39607    39787     +180     
+ Misses       3470     3290     -180     
  Partials       32       32

Impacted Files	Coverage Δ
src/tests/test_cryptobox.cpp	77.27% <0%> (-9.1%)	⬇️
src/lib/tls/tls_session_key.cpp	92.1% <0%> (-7.9%)	⬇️
src/lib/tls/tls_client.cpp	84.25% <0%> (ø)	⬆️
src/lib/tls/tls_extensions.cpp	92.4% <0%> (+0.31%)	⬆️
src/lib/tls/tls_channel.cpp	79.45% <0%> (+0.34%)	⬆️
src/tests/unit_tls.cpp	91.38% <0%> (+0.42%)	⬆️
src/lib/tls/tls_handshake_state.cpp	83.63% <0%> (+0.45%)	⬆️
src/lib/tls/tls_server.cpp	84.06% <0%> (+0.62%)	⬆️
src/lib/prov/openssl/openssl_ec.cpp	91.85% <0%> (+0.74%)	⬆️
src/lib/block/threefish/threefish.cpp	91.83% <0%> (+1.02%)	⬆️
... and 7 more

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