base gcc does not understand -Wwrite-strings and errors out.

Index: CMakeLists.txt
--- CMakeLists.txt.orig
+++ CMakeLists.txt
@@ -512,7 +512,7 @@ if(CMAKE_COMPILER_IS_GNUCC OR "${CMAKE_C_COMPILER_ID}"
   check_c_compiler_flag(-Wredundant-decls HAVE_GCC_REDUNDANT_DECLS)
   check_c_compiler_flag(-Wunreachable-code HAVE_GCC_UNREACHABLE_CODE)
   check_c_compiler_flag(-Wvarargs HAVE_GCC_VARARGS)
-  set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -fvisibility=hidden -Wno-deprecated -Wall -Wno-unknown-pragmas -Wextra -Winit-self -Wunused -Wno-div-by-zero -Wundef -Wpointer-arith -Wtype-limits -Wwrite-strings -Werror=return-type")
+  set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -fvisibility=hidden -Wno-deprecated -Wall -Wno-unknown-pragmas -Wextra -Winit-self -Wunused -Wno-div-by-zero -Wundef -Wpointer-arith -Wtype-limits -Werror=return-type")
   if(HAVE_GCC_UNUSED_BUT_SET)
     set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -Wunused-but-set-variable")
   endif()
@@ -552,7 +552,7 @@ if(CMAKE_COMPILER_IS_GNUCXX OR "${CMAKE_CXX_COMPILER_I
   check_cxx_compiler_flag(-Wredundant-decls HAVE_GXX_REDUNDANT_DECLS)
   check_cxx_compiler_flag(-Wunreachable-code HAVE_GXX_UNREACHABLE_CODE)
   check_cxx_compiler_flag(-Wvarargs HAVE_GXX_VARARGS)
-  set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -fvisibility=hidden -Weffc++ -Wno-deprecated -Wall -Wextra -Woverloaded-virtual -Winit-self -Wunused -Wno-div-by-zero -Wundef -Wpointer-arith -Wtype-limits -Wwrite-strings -Werror=return-type")
+  set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -fvisibility=hidden -Weffc++ -Wno-deprecated -Wall -Wextra -Woverloaded-virtual -Winit-self -Wunused -Wno-div-by-zero -Wundef -Wpointer-arith -Wtype-limits -Werror=return-type")
   if(HAVE_GXX_UNUSED_BUT_SET)
     set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wunused-but-set-variable")
   endif()