Check for an actual library symbol in order to link Win32-specific libs.

Author: jedisct1

configure.ac

@@ -240,9 +240,9 @@ AC_SEARCH_LIBS(recvfrom, [socket])
 AC_SEARCH_LIBS(kvm_open, [kvm])
 
 AS_IF([echo `(uname -s) 2>/dev/null` | $GREP "CYGWIN" > /dev/null], [
-  AC_CHECK_LIB([ws2_32], [printf])
-  AC_CHECK_LIB([psapi], [printf])
-  AC_CHECK_LIB([iphlpapi], [printf])
+  AC_CHECK_LIB([ws2_32], [_head_libws2_32_a])
+  AC_CHECK_LIB([psapi], [_head_libpsapi_a])
+  AC_CHECK_LIB([iphlpapi], [_head_libiphlpapi_a])
 ], [ ])
 
 AC_CHECK_HEADER([CoreServices/CoreServices.h],