external: new subdirectory for all external libraries and submodules.

You will want to 'make distclean' after this.

I also removed libsecp; we use the one in in libwally anyway.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

external/libwally-core/tools/swigjavapost.sh

@@ -0,0 +1,16 @@
+#!/bin/sh
+
+sed_exe=$1
+
+result="swig_java/src/com/blockstream/libwally/Wally.java"
+
+mkdir -p `dirname $result`
+
+# Merge the constants and JNI interface into Wally.java
+grep -v '^}$' swig_java/wallycoreJNI.java | $sed_exe 's/wallycoreJNI/Wally/g' >$result
+grep 'public final static' swig_java/wallycoreConstants.java >>$result
+# Append our extra functionality
+cat swig_java/jni_extra.java_in >>$result
+
+# Clean up
+rm -f swig_java/*.java