cmake: compile libs and plugins with -Wall

Change-Id: I1edf236295eeb934943d6ca2aed04241e9cde362
Signed-off-by: Damjan Marion <damarion@cisco.com>
diff --git a/src/cmake/library.cmake b/src/cmake/library.cmake
index 9ed53e9..66b4dff 100644
--- a/src/cmake/library.cmake
+++ b/src/cmake/library.cmake
@@ -20,6 +20,7 @@
   )
 
   add_library(${lib} SHARED ${ARG_SOURCES})
+  target_compile_options(${lib} PRIVATE -Wall)
 
   # library deps
   if(ARG_LINK_LIBRARIES)