Ask lager and immer to always use exceptions

Summary: lager and immer now have a definition for it to always enable exceptions support. When it is well-supported we can drop the `#include <libkazv-config.hpp>` line.

Type: skip

Test Plan: Verify unit tests pass.

Reviewers:

Subscribers:

src/base/CMakeLists.txt

@@ -33,6 +33,7 @@ target_include_directories(kazvbase
   )
 
 target_compile_options(kazvbase PUBLIC "-fexceptions")
+target_compile_definitions(kazvbase PUBLIC -DLAGER_USE_EXCEPTIONS -DIMMER_USE_EXCEPTIONS)
 
 install(TARGETS kazvbase EXPORT libkazvTargets LIBRARY)