cmake: define BUILD_STATIC and BUILD_SHARED for library builds

cmake/Templates.cmake

@@ -64,6 +64,8 @@ function(rosetta_add_library)
 			${arg_SOURCES}
 			${arg_HEADERS})
 		set_target_properties(${static_lib_name} PROPERTIES OUTPUT_NAME "${lib_name}")
+		target_compile_definitions(${static_lib_name} PRIVATE
+			BUILD_STATIC=1)
 		set(targets ${targets} ${static_lib_name})
 
 		if (arg_PUBLIC_INCLUDE_DIRS)
@@ -86,6 +88,8 @@ function(rosetta_add_library)
 				PATH ${arg_PUBLIC_INCLUDE_DIRS})
 		endif ()
 
+		target_compile_definitions(${shared_lib_name} PRIVATE
+			BUILD_SHARED=1)
 		set_target_properties(${shared_lib_name} PROPERTIES
 			SOVERSION 1)
 		target_link_options(${shared_lib_name} PRIVATE -Wl,--soname,${soname})