Index: CMakeLists.txt
--- CMakeLists.txt.orig
+++ CMakeLists.txt
@@ -200,8 +200,6 @@ if(CMAKE_COMPILER_IS_GNU)
     if (GCC_VERSION VERSION_GREATER 7.0 OR GCC_VERSION VERSION_EQUAL 7.0)
       set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -Wformat-overflow=2 -Wformat-truncation")
     endif()
-    set(CMAKE_C_FLAGS_RELEASE     "-O2")
-    set(CMAKE_C_FLAGS_DEBUG       "-O0 -g3")
     set(CMAKE_C_FLAGS_COVERAGE    "-O0 -g3 --coverage")
     set(CMAKE_C_FLAGS_ASAN        "-fsanitize=address -fno-common -fsanitize=undefined -fno-sanitize-recover=all -O3")
     set(CMAKE_C_FLAGS_ASANDBG     "-fsanitize=address -fno-common -fsanitize=undefined -fno-sanitize-recover=all -O1 -g3 -fno-omit-frame-pointer -fno-optimize-sibling-calls")
@@ -211,8 +209,6 @@ endif(CMAKE_COMPILER_IS_GNU)
 
 if(CMAKE_COMPILER_IS_CLANG)
     set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -Wall -Wextra -Wwrite-strings -Wpointer-arith -Wimplicit-fallthrough -Wshadow -Wvla -Wformat=2 -Wno-format-nonliteral")
-    set(CMAKE_C_FLAGS_RELEASE     "-O2")
-    set(CMAKE_C_FLAGS_DEBUG       "-O0 -g3")
     set(CMAKE_C_FLAGS_COVERAGE    "-O0 -g3 --coverage")
     set(CMAKE_C_FLAGS_ASAN        "-fsanitize=address -fno-common -fsanitize=undefined -fno-sanitize-recover=all -O3")
     set(CMAKE_C_FLAGS_ASANDBG     "-fsanitize=address -fno-common -fsanitize=undefined -fno-sanitize-recover=all -O1 -g3 -fno-omit-frame-pointer -fno-optimize-sibling-calls")
@@ -236,7 +232,7 @@ if(MBEDTLS_FATAL_WARNINGS)
     endif(CMAKE_COMPILER_IS_MSVC)
 
     if(CMAKE_COMPILER_IS_CLANG OR CMAKE_COMPILER_IS_GNU)
-        set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -Werror")
+        set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS}")
         if(UNSAFE_BUILD)
             set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -Wno-error=cpp")
             set(CMAKE_C_FLAGS_ASAN "${CMAKE_C_FLAGS_ASAN} -Wno-error=cpp")