added required packages for building tpm2-tss

README.md

@@ -30,6 +30,9 @@ From Ubuntu 20.10 and later, installing `libtss2-dev` should work.
 
 For Ubuntu 20.04, this should be built from source:
 ```
+# Install further required packages for building this lib
+apt install autoconf autoconf-archive libcmocka0 libcmocka-dev procps iproute2 \
+    pkg-config libtool libssl-dev uthash-dev libjson-c-dev libini-config-dev
 # Build the tpm2-tss lib from source
 ../.travis/install-tpm2-tss.sh ./tpm2-tss /usr
 ```