LDFLAGS -ld -lc not detected automatically on Solaris x86

Hello,

I compiled curl on a bunch of systems, maybe you find it useful to hear about the different options I had to set.
Please pay (only) attention to the -lc and -ldl switches.
On a solaris x86 box, the switches -lc and -ldl are needed, but not detected automatically by the configure script.
(It would be nice to have this auto-detect feature in the future).

I could not compile the version 7.25.0 on an ANCIENT AIX 4.3 machine, but the 7.24.0 did it without any problems.
I configured curl on the AIX with the following parameters:

curl-7.25.0/config.log:uname -m = 004640DA4C00
curl-7.25.0/config.log:uname -r = 3
curl-7.25.0/config.log:uname -s = AIX
curl-7.25.0/config.log:uname -v = 4
curl-7.25.0/config.log:CONFIGURE_OPTIONS='" '\''--prefix=/siux_share/ae/cc/laboru2/curl'\'' '\''--with-ssl=/siux_share/ae/cc/laboru2/curl'\''"'

if gcc -DHAVE_CONFIG_H  -I../include/curl -I../include -I../include -I../lib -I../src -I../lib
-I../src  -I/compile/curl/include -I/compile/curl/include/openssl  -g0 -O2 -Wno-system-headers 
-MT tool_operate.o -MD -MP -MF ".deps/tool_operate.Tpo" -c -o tool_operate.o tool_operate.c; \
        then mv -f ".deps/tool_operate.Tpo" ".deps/tool_operate.Po"; else rm -f ".deps/tool_operate.Tpo";
exit 1; fi
In file included from /usr/include/netinet/tcp.h:69,
                 from tool_operate.c:45:
/usr/include/netinet/ip.h:115: error: parse error before "ip_xhl"
/usr/include/netinet/ip.h:121: error: parse error before '}' token
/usr/include/netinet/ip.h:128: error: parse error before '}' token
/usr/include/netinet/ip.h:131: error: field `ip_ff' has incomplete type
/usr/include/netinet/ip.h:144: error: field `ip_src' has incomplete type
/usr/include/netinet/ip.h:144: error: field `ip_dst' has incomplete type
/usr/include/netinet/ip.h:267: error: parse error before "ipt_xcode"