Remove nsl library check in sapi/fpm (php#13478)

In sapi/fpm the inet_ntop is used instead of the deprecated inet_addr
and the required library, if needed, is linked from the configure.ac.

sapi/fpm/config.m4

@@ -5,13 +5,6 @@ PHP_ARG_ENABLE([fpm],,
  [no])
 
 dnl Configure checks.
-AC_DEFUN([AC_FPM_STDLIBS],
-[
- AC_CHECK_FUNCS(clearenv setproctitle setproctitle_fast)
-
- AC_SEARCH_LIBS(inet_addr, nsl)
-])
-
 AC_DEFUN([AC_FPM_CLOCK],
 [
  have_clock_gettime=no
@@ -482,7 +475,6 @@ AC_MSG_CHECKING(for FPM build)
 if test "$PHP_FPM" != "no"; then
  AC_MSG_RESULT($PHP_FPM)
 
- AC_FPM_STDLIBS
  AC_FPM_CLOCK
  AC_FPM_TRACE
  AC_FPM_BUILTIN_ATOMIC
@@ -494,6 +486,8 @@ if test "$PHP_FPM" != "no"; then
  AC_FPM_EPOLL
  AC_FPM_SELECT
 
+ AC_CHECK_FUNCS([clearenv setproctitle setproctitle_fast])
+
  AC_CHECK_HEADER([priv.h], [AC_CHECK_FUNCS([setpflags])])
 
  PHP_ARG_WITH([fpm-user],,