Make aws-lc-fips-sys's config CMAKE_BUILD_TYPE logic same with aws-lc-sys

[honsunrise]

Description of changes:

Define CMAKE_BUILD_TYPE so that CMake can use the correct CMAKE_XXX_FLAGS_XXX.

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[justsmth]

Hello! Thanks for the PR. For CMAKE_BUILD_TYPE, we defer to the logic provided by cmake-rs here.

Is there a particular problem that you're trying to address with this change?

[honsunrise]

Hello! Thanks for the PR. For CMAKE_BUILD_TYPE, we defer to the logic provided by cmake-rs here.

Is there a particular problem that you're trying to address with this change?

Maintain consistency with the logic in aws-lc-fips-sys, so that the CMAKE_BUILD_TYPE has a consistent definition under the same build profile (it seems unnecessary on Windows to require aws-lc-sys to follow "relwithdebinfo"). Of course, if this is not mandatory, following the logic of cmake-rs would seem more elegant.

However, another approach would be for aws-lc-fips-sys to migrate to the cmake-rs logic and handle the Windows case separately, which also seems better. If this is acceptable, I can modify this MR.

[justsmth]

However, another approach would be for aws-lc-fips-sys to migrate to the cmake-rs logic and handle the Windows case separately, which also seems better. If this is acceptable, I can modify this MR.

Yeah, that logic in aws-lc-fips-sys is really only needed on Windows due to our FIPS build on Windows not supporting debug.