diff --git a/CMakeLists.txt b/CMakeLists.txt
index 5eeea4db5..cd4145c88 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -42,14 +42,15 @@ endif()
 # Enable a whole bunch of warnings, but turn off:
 # - comment because we use a bunch of those, and they're not really all that harmful.
 # - address, because that occurs for our mkostemp check (weak-linking requires us to compare `&mkostemp == nullptr`).
-set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wall -Wextra \
--Wno-comment \
--Wno-address \
-")
+set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wall -Wextra -Wno-comment -Wno-address -Wunused-template \
+  -Wunused-function -Wunused-local-typedef -Wunused-lambda-capture -Wunused-macros -Wunused-variable")
 
 # Disable exception handling.
 add_compile_options(-fno-exceptions)
 
+# Undefine NDEBUG to keep assert() in release builds.
+add_definitions(-UNDEBUG)
+
 # Hide the CMake Rules directories in Xcode projects.
 source_group("CMake Rules" REGULAR_EXPRESSION "^$")