Stop calling SystemTime for wasm32 target

[jjyr]

The SystemTime::now in ChannelManager compiles on the wasm32- target, but it causes panic. We should use more strict compiling condition.

rust-lang/rust#48564 (comment)

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 89.57%. Comparing base (b023eed) to head (4f0e821).
Report is 183 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #3358      +/-   ##
==========================================
- Coverage   89.82%   89.57%   -0.25%     
==========================================
  Files         126      127       +1     
  Lines      103854   103533     -321     
  Branches   103854   103533     -321     
==========================================
- Hits        93285    92738     -547     
- Misses       7843     8092     +249     
+ Partials     2726     2703      -23     

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[tnull]

I agree we should fix this, but we probably should finally come up with a more comprehensive strategy across all our crates that is also properly documented and checked in CI.

@TheBlueMatt, in lightning-transaction-sync we introduced the time feature to discern the std-but-no-std::time. Should we do the same across all other crates?

[TheBlueMatt]

We do have a comprehensive strategy as of 0.0.124 - if you don't want to call system time, build with no-std/no-std. You can still turn std on in rust-bitcoin/bitcoin-io or other crates as its no longer totally infectious.

[tnull]

We do have a comprehensive strategy as of 0.0.124 - if you don't want to call system time, build with no-std/no-std. You can still turn std on in rust-bitcoin/bitcoin-io or other crates as its no longer totally infectious.

Ah, sorry, true, it should work by just not using the std feature.