configure: "netinet/in_systm.h" is optional

The header file "netinet/in_systm.h" already is optional in ngIRCd, so
don't require it in the configure script. Now ngIRCd can be built on
Minix 3 again :-)
(cherry picked from commit fd260404caa7ce174ada663024d19cd789c152b5)

diff --git a/configure.ng b/configure.ng
index 01da7f6cf8d853056c13ac43a445c093a48bfcbc..5ae1c0e5c3bd1438d5008628e6b9cbf4371d544d 100644 (file)
--- a/configure.ng
+++ b/configure.ng
@@ -120,14 +120,14 @@ AC_HEADER_TIME
 
 # Required header files
 AC_CHECK_HEADERS([ \
-       fcntl.h netdb.h netinet/in.h netinet/in_systm.h stdlib.h string.h \
+       fcntl.h netdb.h netinet/in.h stdlib.h string.h \
        strings.h sys/socket.h sys/time.h unistd.h \
        ],,AC_MSG_ERROR([required C header missing!]))
 
 # Optional header files
 AC_CHECK_HEADERS_ONCE([ \
-       arpa/inet.h inttypes.h malloc.h netinet/ip.h stdbool.h stddef.h \
-       stdint.h varargs.h \
+       arpa/inet.h inttypes.h malloc.h netinet/in_systm.h netinet/ip.h \
+       stdbool.h stddef.h stdint.h varargs.h \
        ])
 
 # -- Datatypes --