programs: cmake: Fix relative path warnings

The path to source files were relative which triggered
warnings when generating the build system.

Move to absolute paths based on CMAKE_CURRENT_SOURCE_DIR.

Signed-off-by: Ronald Cron <ronald.cron@arm.com>
diff --git a/programs/ssl/CMakeLists.txt b/programs/ssl/CMakeLists.txt
index aaa9a0a..d6ba2ac 100644
--- a/programs/ssl/CMakeLists.txt
+++ b/programs/ssl/CMakeLists.txt
@@ -39,7 +39,7 @@
 target_link_libraries(ssl_client1 ${libs})
 
 add_executable(ssl_client2 ssl_client2.c)
-target_sources(ssl_client2 PUBLIC ../test/query_config.c)
+target_sources(ssl_client2 PUBLIC ${CMAKE_CURRENT_SOURCE_DIR}/../test/query_config.c)
 target_link_libraries(ssl_client2 ${libs})
 
 add_executable(ssl_context_info ssl_context_info.c)
@@ -55,7 +55,7 @@
 target_link_libraries(ssl_server ${libs})
 
 add_executable(ssl_server2 ssl_server2.c)
-target_sources(ssl_server2 PUBLIC ../test/query_config.c)
+target_sources(ssl_server2 PUBLIC ${CMAKE_CURRENT_SOURCE_DIR}/../test/query_config.c)
 target_link_libraries(ssl_server2 ${libs})
 
 if(THREADS_FOUND)