Honor the standard BUILD_SHARED_LIBS cmake variable.

The variable switches the default type for add_library from STATIC to SHARED.
We can condition additional stuff on that for convenience. (tabtest still
doesn't build.)

BoringSSL as any kind of stable system shared library is still very much
unsupported, but this is probably handy for making sure we don't forget all
those pesky OPENSSL_EXPORTs.

Change-Id: I66ab80bcddbf3724e03e85384141fdf4f4acbc2e
Reviewed-on: https://boringssl-review.googlesource.com/3092
Reviewed-by: Adam Langley <agl@google.com>
4 files changed