[Docs] Add prerequisite libcurl4-openssl-dev to Build and Quick Start docs

Documentation/building.rst

@@ -32,7 +32,8 @@ Run the following command on Ubuntu to install dependencies for Graphene::
 
 For building Graphene for SGX, run the following command in addition::
 
-    sudo apt-get install -y libprotobuf-c-dev protobuf-c-compiler
+    sudo apt-get install -y libprotobuf-c-dev protobuf-c-compiler \
+       libcurl4-openssl-dev
 
     # For Ubuntu 18.04
     sudo apt-get install -y python3-protobuf

Documentation/quickstart.rst

@@ -76,7 +76,7 @@ second command should list the process status of :command:`aesm_service`.
 #. Build Graphene-SGX::
 
       sudo apt-get install -y \
-         build-essential autoconf gawk bison \
+         build-essential autoconf gawk bison libcurl4-openssl-dev \
          python3-protobuf libprotobuf-c-dev protobuf-c-compiler
       cd $GRAPHENE_DIR
       make SGX=1