Merge pull request jitsi#243 from jitsi/update-usrsctp-build-instruct…

…ions

new README.md file for building the usrsctp lib.

src/native/sctp/README.md

@@ -0,0 +1,15 @@
+# Build Instructions
+
+## Building the usrsctp static lib
+1. Checkout usrsctp source:
+  * `cd src/native/sctp`
+  * `git clone https://github.com/sctplab/usrsctp.git`
+2. Build usrsctp
+  * `cd src/native/sctp/usrsctp`
+  * `./configure --with-pic`
+  * `make`
+
+## Building the java jni wrapper lib
+1. From `libjitsi/` run `ant -v -lib ~/.m2/repository/org/apache/maven/maven-ant-tasks/2.1.3 sctp -Dusrsctp=<LOCATION_OF_SCTP_DIR>`
+2. When setting the location of the sctp dir, it's easiest to use an absolute path, as otherwise it will be taken relative to a directoy a few levels below.  NOTE: If you don't pass your sctp dir in correctly, the build will end up using the system usrsctp lib (if there is one)
+3. A new libjnsctp.so will be put in `libjitsi/lib/native/<your_arch>`