[tnozaki-gdtoa] overriding ACQUIRE_DTOA_LOCK/FREE_DTOA_LOCK macro

[Takehiko NOZAKI]

it seems gdtoa defines these macros related -DMULTIPLE_THREADS

#ifdef MULTIPLE_THREADS /*{{*/
#define MTa , PTI
#define MTb , &TI
#define MTd , ThInfo **PTI
#define MTk ThInfo **PTI;
extern void ACQUIRE_DTOA_LOCK ANSI((unsigned int));
extern void FREE_DTOA_LOCK ANSI((unsigned int));
extern unsigned int dtoa_get_threadno ANSI((void));
#else /*}{*/
#define ACQUIRE_DTOA_LOCK(n)    /*nothing*/
#define FREE_DTOA_LOCK(n)       /*nothing*/
#define MTa /*nothing*/
#define MTb /*nothing*/
#define MTd /*nothing*/
#define MTk /*nothing*/
#endif /*}}*/

user have to provide implementation to these macros, N* use __libc_mutex_* for this.

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