Which header a symbol is declared in (AC_CHECK_DECLS) ?

[Konstantin Andreev]

Hello.

Could you advise, how to correctly determine which header a symbol is
declared in ?

I assumed that I can write something like this:

  AC_CHECK_DECLS([bzero],[],[],[[#include <string.h>]])
  if .. not .. declared ..
    AC_CHECK_DECLS([bzero],[],[],[[#include <strings.h>]])
  if .. not .. declared .. again
    conclude there is no symbol 'bzero'

Unfortunately, AC_CHECK_DECLS remembers the result of the 1st check. 

When I call it next time, AC_CHECK_DECLS refuses to check symbol against
other header and reproduces the old result.

Best regards,
--
Konstantin Andreev.