ubench use `asm` instead of `__asm__` leads to compile fail

[loynoir]

bug

ubench use asm instead of __asm__ leads to compile fail

reproduce

==> a1.c <==

#include "ubench.h"

UBENCH(foo, bar) {}
UBENCH_MAIN();

==> a2.c <==

#define asm __asm__

#include "ubench.h"

UBENCH(foo, bar) {}
UBENCH_MAIN();

actual

OK when -std=gnu17

% gcc -std=gnu17 a1.c -lm && echo OK
OK

compile fail when -std=c17

% gcc -std=c17 a1.c -lm && echo OK
In file included from a1.c:1:
a1.c: In function ‘ubench_do_nothing’:
ubench.h:882:5: error: ‘asm’ undeclared (first use in this function)
  882 |     asm volatile("" : : "r"(ptr), "m"(ptr) : "memory");                        \
      |     ^~~
ubench.h:896:3: note: in expansion of macro ‘UBENCH_DECLARE_DO_NOTHING’
  896 |   UBENCH_DECLARE_DO_NOTHING()                                                  \
      |   ^~~~~~~~~~~~~~~~~~~~~~~~~
ubench.h:907:3: note: in expansion of macro ‘UBENCH_STATE’
  907 |   UBENCH_STATE();                                                              \
      |   ^~~~~~~~~~~~
a1.c:4:1: note: in expansion of macro ‘UBENCH_MAIN’
    4 | UBENCH_MAIN();
      | ^~~~~~~~~~~
ubench.h:882:5: note: each undeclared identifier is reported only once for each function it appears in
  882 |     asm volatile("" : : "r"(ptr), "m"(ptr) : "memory");                        \
      |     ^~~
ubench.h:896:3: note: in expansion of macro ‘UBENCH_DECLARE_DO_NOTHING’
  896 |   UBENCH_DECLARE_DO_NOTHING()                                                  \
      |   ^~~~~~~~~~~~~~~~~~~~~~~~~
ubench.h:907:3: note: in expansion of macro ‘UBENCH_STATE’
  907 |   UBENCH_STATE();                                                              \
      |   ^~~~~~~~~~~~
a1.c:4:1: note: in expansion of macro ‘UBENCH_MAIN’
    4 | UBENCH_MAIN();
      | ^~~~~~~~~~~
ubench.h:882:9: error: expected ‘;’ before ‘volatile’
  882 |     asm volatile("" : : "r"(ptr), "m"(ptr) : "memory");                        \
      |         ^~~~~~~~
ubench.h:896:3: note: in expansion of macro ‘UBENCH_DECLARE_DO_NOTHING’
  896 |   UBENCH_DECLARE_DO_NOTHING()                                                  \
      |   ^~~~~~~~~~~~~~~~~~~~~~~~~
ubench.h:907:3: note: in expansion of macro ‘UBENCH_STATE’
  907 |   UBENCH_STATE();                                                              \
      |   ^~~~~~~~~~~~
a1.c:4:1: note: in expansion of macro ‘UBENCH_MAIN’
    4 | UBENCH_MAIN();
      | ^~~~~~~~~~~

workaround

% gcc -std=c17 a2.c -lm && echo OK
OK

[sheredom]

Happy to accept a PR.