Compiler/CC2538DK: "error #18: expected a ")"" in __asm__ volatile instruction of Contiki project

Part Number: CC2538DK

Tool/software: TI C/C++ Compiler

Hello everyone.

I am studying the Contiki OS, most specifically, trying to develop an application using such OS.
Bearing in mind that I pretended to Debug the Contiki OS in CC2538DK using the CCS (I'm using the 9.1 version in native 64-bits ubuntu) I am trying to build the Contiki project over the blink led example for cc2538dk provided by CCS examples.

I've encountered many issues during this integration but always managed to solve them with help of other issues in these forums.
I can't seem to find the solution for this:

"../cpu/arm/common/sys/mtarch.c", line 249: error #18: expected a ")"
1 error detected in the compilation of "../cpu/arm/common/sys/mtarch.c".
gmake: *** [cpu/arm/common/sys/mtarch.obj] Error 1

The "faulty" function is the following:

void mtarch_exec(struct mtarch_thread *thread)
{
  /* Pass the PSP to SVCall, and get the updated PSP as its return value. */
  register uint32_t psp_aux __asm__ ("r0") = thread->psp;

  __asm__ volatile ("svc #0"
                     : "+r" (psp_aux)          // this is the line 249 where the error is pointed out
                     :: "memory");

  thread->psp = psp_aux;
}

I remind you that this projects builds with no problems with gcc and these only occur, I guess, since I'm trying to build it with TI's compiler.
Can anyone give me some hint for where the problem might be?

Thank you in advance for the attention and help.