drop optimization flag and -Werror

Index: src/CMakeLists.txt
--- src/CMakeLists.txt.orig
+++ src/CMakeLists.txt
@@ -127,7 +127,7 @@ endif()
 # FIXME(compnerd) add check for -fblocks?
 target_compile_options(dispatch PRIVATE -fblocks)
 
-check_c_compiler_flag("-momit-leaf-frame-pointer -Werror -Wall -O3" C_SUPPORTS_OMIT_LEAF_FRAME_POINTER)
+check_c_compiler_flag("-momit-leaf-frame-pointer -Wall" C_SUPPORTS_OMIT_LEAF_FRAME_POINTER)
 if (C_SUPPORTS_OMIT_LEAF_FRAME_POINTER)
   target_compile_options(dispatch PRIVATE -momit-leaf-frame-pointer)
 endif()