improve wording

Author: gareth-nx

README.md

@@ -134,7 +134,7 @@ Important options are
 - `-DBUILD_SHARED_LIBS` set to `on` in case you want link your application dynamically against the standard library (default: `off`).
 - `-DBUILD_TESTING` set to `off` in case you want to disable the stdlib tests (default: `on`).
 - `-DCMAKE_VERBOSE_MAKEFILE` is by default set to `Off`, but if set to `On` will show commands used to compile the code.
-- `-DCMAKE_BUILD_TYPE` is by default set to `RelWithDebInfo` which uses compiler flags suitable for code development (but with only `-O2` optimization). These options may override compiler flags that are specified via `FFLAGS`. To avoid this, use the value `-DCMAKE_BUILD_TYPE=NoConfig` in conjunction with `FFLAGS`.
+- `-DCMAKE_BUILD_TYPE` is by default set to `RelWithDebInfo`, which uses compiler flags suitable for code development (but with only `-O2` optimization). Beware the compiler flags set this way will override any compiler flags specified via `FFLAGS`. To prevent this, use `-DCMAKE_BUILD_TYPE=NoConfig` in conjunction with `FFLAGS`.
 
 For example, to configure a build using the Ninja backend while specifying compiler optimization via `FFLAGS`, generating procedures up to rank 7, installing to your home directory, using the `NoConfig` compiler flags, and printing the compiler commands, use