Using javac to generate header

jni/android/src/main/AndroidManifest.xml

@@ -0,0 +1,3 @@
+<?xml version="1.0" encoding="utf-8"?>
+<manifest package="fr.acinq.secp256k1.jni">
+</manifest>

jni/android/src/main/CMakeLists.txt

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+cmake_minimum_required(VERSION 3.10.0)
+
+add_library( secp256k1-jni SHARED
+    ${CMAKE_CURRENT_LIST_DIR}/../../../../native/jni/src/org_bitcoin_Secp256k1CFunctions.c
+)
+
+target_include_directories( secp256k1-jni
+    PUBLIC ${CMAKE_CURRENT_LIST_DIR}/../../../../native/secp256k1
+    PUBLIC ${CMAKE_CURRENT_LIST_DIR}/../../../../native/jni/headers/java
+)
+
+target_link_libraries( secp256k1-jni
+    ${CMAKE_CURRENT_LIST_DIR}/../../../../native/build/android/${ANDROID_ABI}/libsecp256k1.a
+)

jni/android/src/main/kotlin/fr/acinq/secp256k1/jni/NativeSecp256k1Loader.kt

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+package fr.acinq.secp256k1.jni
+
+import fr.acinq.secp256k1.Secp256k1
+import org.bitcoin.NativeSecp256k1
+
+public object NativeSecp256k1Loader {
+
+    @JvmStatic
+    @Synchronized
+    @Throws(Exception::class)
+    fun load(): Secp256k1 {
+        System.loadLibrary("secp256k1-jni")
+        return NativeSecp256k1
+    }
+
+}