docs: cgo secp256k1 ldflags (#18357)

Co-authored-by: Marko <[email protected]>

crypto/keys/secp256k1/internal/secp256k1/README.md

@@ -3,3 +3,17 @@
  This package is copied from https://github.com/ethereum/go-ethereum/tree/8fddf27a989e246659fd018ea9be37b2b4f55326/crypto/secp256k1
 
  Unlike the rest of go-ethereum it is [3-clause BSD](https://opensource.org/licenses/BSD-3-Clause) licensed so compatible with our Apache2.0 license. We opt to copy in here rather than depend on go-ethereum to avoid issues with vendoring of the GPL parts of that repository by downstream.
+
+## Duplicate Symbols
+
+If a project is importing [go-ethereum](https://github.com/ethereum/go-ethereum) and the Cosmos SDK, cgo secp256k1 will only work on linux operating systems due to duplicated symbols. If you are testing on a mac, we recommend using a docker container or something similar. 
+
+To avoid duplicate symbol errors `ldflags` must be set to allow for multiple definitions. 
+
+#### Gcc
+
+ + `go build -tags libsecp256k1_sdk  -ldflags=all="-extldflags=-Wl,--allow-multiple-definition"`
+
+#### Clang
+
+ + `go build -tags libsecp256k1_sdk -ldflags=all="-extldflags=-zmuldefs"`