these should include the correct headers that declare the functions they
are using.
configure:20429: checking for accept4 support
/src/build/apr/apr-1.4.6/config.log:conftest.c:72:9: error: implicit
declaration of function 'strncpy'
configure:22070: checking for inet_addr
this check has 2 issues:
a) it does the check twice if the first test succeeds, wasting precious time
b) it uses sizeof(( $2 )) in the second ac_fn_c_try_compile invocation
which is invalid C
root:/src$ cat test.c
typedef unsigned long size_t;
int main () {
if (sizeof ((size_t)))
return
