Assembler directives confuse compiler?

I’ve just installed MBed Studio 0.8.1, which is working well with blinky example on NXP LPCXpresso 54114 evaluation board.

I’m trying to run FFT examples using CMSIS-DSP library, but some .directives in the single assembly file arm_bitreversal2.S in the library are confusing the Studio.
https://arm-software.github.io/CMSIS_5/DSP/html/group__FrequencyBin.html

The compiler dislikes the dot-directives :
#elif defined (GNUC) // GCC
#define THUMB .thumb
#define CODESECT .section .text
#define EXPORT .global
.syntax unified

The latest CMSIS-DSP I can find for mbed is 1.5.0 - looks like the .S assembly was converted to .C in 1.5.3 and above but I don’t see where to get a more current DSP library. It’s presently up to 1.7.0

Issue also noted by someone else two years ago - Trying to use CMSIS-DSP with mbed-os... | Mbed

My workaround was to copy over just arm_bitreversal_32.c from the 1.7.0 library into my project, and remove the .S file from the TransformFunctions folder of the CMSIS_DSP_5 1.5.0 library.