Runner Type: Xcode Project Additional command line parameters removing quotes

The runner type is Xcode Project

When running a build I am adding in additional command line parameters in order to set variables in the the Xcode project for the build.  

E.g.

TEAMCITY_BUILD_NUMBER="%build.number%"

(Where build.number = 999)

Becomes: 

Build settings from command line:
TEAMCITY_BUILD_NUMBER = 999

Under normal circumstances this works, but in this can I am setting a parameter that has to be put into Xcode that has its own parameters separated by spaces so they must be within quotes

E.g. 

TEAMCITY_CMAKE_CONFIGURE_SETTINGS="%C_FLAG%"

(Where C_FLAG = C_FLAGS=-fsanitize=address -fsanitize=undefined)

Becomes:

Build settings from command line:
TEAMCITY_CMAKE_CONFIGURE_SETTINGS = -DCMAKE_C_FLAGS=-fsanitize=address -fsanitize=undefined

This is not acceptable as -fsanitize=undefined is read in by Xcode as a separate parameter.
 
For it to be read in correctly it must show 

TEAMCITY_CMAKE_CONFIGURE_SETTINGS = -DCMAKE_C_FLAGS="-fsanitize=address -fsanitize=undefined"

So I tried changing C_FLAG to C_FLAGS="\"-fsanitize=address -fsanitize=undefined\""

Which works on the command line, but not on Xcode Project which converts it to 

\"-DCMAKE_C_FLAGS=-fsanitize=address -fsanitize=undefined \"

From that input it is shown to either not put the quotes in the correct space to escape the inner quotes or is ignoring the inner quotes

Thanks