https://bugs.gentoo.org/746770
--- a/cmake/modules/c_flags.cmake
+++ b/cmake/modules/c_flags.cmake
@@ -50,5 +50,4 @@ if (${CMAKE_BUILD_TYPE} MATCHES "Debug")
     add_cflag_if_supported("-O0")
 else ()
     add_cflag_if_supported("-O2")
-    add_cflag_if_supported("-Werror")
 endif ()
--- a/doc/dev/app-example/CMakeLists.txt
+++ b/doc/dev/app-example/CMakeLists.txt
@@ -14,7 +14,7 @@ include_directories(${STLINK_INCLUDE_DIRS})
 find_package(PkgConfig)
 pkg_check_modules(STLINK REQUIRED stlink)
 
-set(CMAKE_C_FLAGS " ${STLINK_CFLAGS_OTHER} -Wall -Werror")
+set(CMAKE_C_FLAGS " ${STLINK_CFLAGS_OTHER} -Wall")
 
 add_executable(${PROJECT_NAME} ${SRCS})