-test -z "$ac_cv_header_strings_h" && AC_CHECK_HEADERS(strings.h)
-test -z "$ac_cv_header_stdlib_h" && AC_CHECK_HEADERS(stdlib.h)
-test -z "$ac_cv_header_unistd_h" && AC_CHECK_HEADERS(unistd.h)
-AC_MSG_CHECKING([whether $1 is declared])
-AC_CACHE_VAL(jm_cv_func_decl_$1,
-[AC_TRY_COMPILE([
-#include <stdio.h>
-#ifdef HAVE_STRING_H
-# include <string.h>
-#else
-# ifdef HAVE_STRINGS_H
-# include <strings.h>
-# endif
-#endif
-#ifdef HAVE_STDLIB_H
-# include <stdlib.h>
-#endif
-#ifdef HAVE_UNISTD_H
-# include <unistd.h>
-#endif],
-[
+ AC_MSG_CHECKING([whether $1 is declared])
+ AC_CACHE_VAL(jm_cv_func_decl_$1,
+ [AC_TRY_COMPILE($2,
+ [