Remove secp256k1 from codebase and clone for macOS and iOS

Author: MatthewLM

coinlib_flutter/darwin/Classes/coinlib_flutter.c

@@ -1,6 +1,6 @@
 // Relative import to be able to reuse the C sources.
 // See the comment in ../{projectName}}.podspec for more information.
-#include "../../src/secp256k1/src/secp256k1.c"
-#include "../../src/secp256k1/src/precompute_ecmult_gen.c"
-#include "../../src/secp256k1/src/precomputed_ecmult_gen.c"
-#include "../../src/secp256k1/src/precomputed_ecmult.c"
+#include "../build/secp256k1/src/secp256k1.c"
+#include "../build/secp256k1/src/precompute_ecmult_gen.c"
+#include "../build/secp256k1/src/precomputed_ecmult_gen.c"
+#include "../build/secp256k1/src/precomputed_ecmult.c"

coinlib_flutter/darwin/coinlib_flutter.podspec

@@ -1,7 +1,11 @@
-#
-# To learn more about a Podspec see http://guides.cocoapods.org/syntax/podspec.html.
-# Run `pod lib lint coinlib_flutter.podspec` to validate before publishing.
-#
+# Clone secp256k1 0.5.0 code into ./build/secp256k1
+`
+mkdir build
+git clone https://github.com/bitcoin-core/secp256k1 build/secp256k1
+cd build/secp256k1
+git checkout e3a885d42a7800c1ccebad94ad1e2b82c4df5c65
+`
+
 Pod::Spec.new do |s|
   s.name             = 'coinlib_flutter'
   s.module_name      = 'secp256k1'