-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_$1,
-[AC_TRY_COMPILE([
+ AC_REQUIRE([AC_HEADER_STDC])dnl
+ test -z "$ac_cv_header_memory_h" && AC_CHECK_HEADERS(memory.h)
+ test -z "$ac_cv_header_string_h" && AC_CHECK_HEADERS(string.h)
+ test -z "$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([