ssl_test_lib.[hc]: new source file for common SSL test code

Create a new source file for code that is shared between ssl_client2.c
and ssl_server2.c. This commit only creates the file; subsequent
commits will populate it.

Add it to the official build systems (make, cmake, VS).

Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
diff --git a/visualc/VS2010/ssl_client2.vcxproj b/visualc/VS2010/ssl_client2.vcxproj
index 9021602..9884f23 100644
--- a/visualc/VS2010/ssl_client2.vcxproj
+++ b/visualc/VS2010/ssl_client2.vcxproj
@@ -21,6 +21,7 @@
   <ItemGroup>

     <ClCompile Include="..\..\programs\ssl\ssl_client2.c" />

     <ClCompile Include="..\..\programs\test\query_config.c" />

+    <ClCompile Include="..\..\programs\ssl\ssl_test_lib.c" />

   </ItemGroup>

   <ItemGroup>

     <ProjectReference Include="mbedTLS.vcxproj">

diff --git a/visualc/VS2010/ssl_server2.vcxproj b/visualc/VS2010/ssl_server2.vcxproj
index 61eedaa..d8f3e59 100644
--- a/visualc/VS2010/ssl_server2.vcxproj
+++ b/visualc/VS2010/ssl_server2.vcxproj
@@ -21,6 +21,7 @@
   <ItemGroup>

     <ClCompile Include="..\..\programs\ssl\ssl_server2.c" />

     <ClCompile Include="..\..\programs\test\query_config.c" />

+    <ClCompile Include="..\..\programs\ssl\ssl_test_lib.c" />

   </ItemGroup>

   <ItemGroup>

     <ProjectReference Include="mbedTLS.vcxproj">