cmake: Introduce version and soversion variables

Signed-off-by: Ronald Cron <ronald.cron@arm.com>
diff --git a/CMakeLists.txt b/CMakeLists.txt
index 12ddc27..659fd50 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -37,15 +37,20 @@
 # is deprecated and will be removed in future versions.
 cmake_policy(SET CMP0012 NEW)
 
+set(MBEDTLS_VERSION 4.0.0)
+set(MBEDTLS_CRYPTO_SOVERSION 17)
+set(MBEDTLS_X509_SOVERSION 8)
+set(MBEDTLS_TLS_SOVERSION 22)
+
 if(TEST_CPP)
     project("Mbed TLS"
         LANGUAGES C CXX
-        VERSION 4.0.0
+        VERSION ${MBEDTLS_VERSION}
     )
 else()
     project("Mbed TLS"
         LANGUAGES C
-        VERSION 4.0.0
+        VERSION ${MBEDTLS_VERSION}
     )
 endif()