--- configure.ac.ori	2011-07-03 02:00:53.000000000 +0200
+++ configure.ac	2011-07-03 02:10:41.000000000 +0200
@@ -147,72 +147,80 @@
 AC_CHECK_FUNCS([gettimeofday memset select socket strchr])
 
 # Is this Solaris?
-AC_MSG_CHECKING(for Solaris)
-AC_RUN_IFELSE([AC_LANG_PROGRAM( [], [
+AC_CACHE_CHECK([for Solaris], ac_cv_os_solaris,
+	[AC_TRY_RUN([
 #if defined (__SVR4) && defined (__sun)
 	exit(0);
 #else
 	exit(-1);
 #endif
-		])
-	],[
-		AC_MSG_RESULT(yes)
-		AC_DEFINE([HAVE_SOLARIS], 1, [Is this a Solaris system?])
-		HAVE_SOLARIS=yes
-	],[
-		AC_MSG_RESULT(no)
-	])
+	],
+	ac_cv_os_solaris=yes,
+	ac_cv_os_solaris=no,
+	ac_cv_os_solaris=no	dnl cross-compiling, assuming is not
+)])
+AS_IF([test x$ac_cv_os_solaris = xyes],
+	[AC_DEFINE([HAVE_SOLARIS], 1, [Is this a Solaris system?])
+	 HAVE_SOLARIS=yes
+	]
+)
 
 # Is this BSDI?
-AC_MSG_CHECKING(for BSDI)
-AC_RUN_IFELSE([AC_LANG_PROGRAM( [], [
+AC_CACHE_CHECK([for BSDI], ac_cv_os_bsdi,
+	[AC_TRY_RUN([
 #if defined (__bsdi__)
 	exit(0);
 #else
 	exit(-1);
 #endif
-		])
-	],[
-		AC_MSG_RESULT(yes)
-		AC_DEFINE([HAVE_BSDI], 1, [Is this a BSDI system?])
-		HAVE_BSDI=yes
-	],[
-		AC_MSG_RESULT(no)
-	])
+	],
+	ac_cv_os_bsdi=yes,
+	ac_cv_os_bsdi=no,
+	ac_cv_os_bsdi=no	dnl cross-compiling, assuming is not
+)]) 
+AS_IF([test x$ac_cv_os_bsdi = xyes],
+	[AC_DEFINE([HAVE_BSDI], 1, [Is this a BSDI system?])
+	 HAVE_BSDI=yes
+	]
+)
 
 # Is this NetBSD?
-AC_MSG_CHECKING(for NetBSD)
-AC_RUN_IFELSE([AC_LANG_PROGRAM( [], [
+AC_CACHE_CHECK([for NetBSD], ac_cv_os_netbsd,
+	[AC_TRY_RUN([
 #if defined (__NetBSD__)
 	exit(0);
 #else
 	exit(-1);
 #endif
-		])
-	],[
-		AC_MSG_RESULT(yes)
-		AC_DEFINE([HAVE_NETBSD], 1, [Is this a NetBSD system?])
-		HAVE_NETBSD=yes
-	],[
-		AC_MSG_RESULT(no)
-	])
+	],
+	ac_cv_os_netbsd=yes,
+	ac_cv_os_netbsd=no,
+	ac_cv_os_netbsd=no	dnl cross-compiling, assuming is not
+)])
+AS_IF([test x$ac_cv_os_netbsd = xyes],
+	[AC_DEFINE([HAVE_NETBSD], 1, [Is this a NetBSD system?])
+	 HAVE_NETBSD=yes
+	]
+)
 
 # Is this MacOS X?
-AC_MSG_CHECKING(for MacOS X)
-AC_RUN_IFELSE([AC_LANG_PROGRAM( [], [
+AC_CACHE_CHECK([for MacOS X], ac_cv_os_macosx,
+	[AC_TRY_RUN([
 #if defined (__APPLE__) && defined (__MACH__)
 	exit(0);
 #else
 	exit(-1);
 #endif
-		])
-	],[
-		AC_MSG_RESULT(yes)
-		AC_DEFINE([HAVE_MACOSX], 1, [Is this a MacOS X system?])
-		HAVE_MACOSX=yes
-	],[
-		AC_MSG_RESULT(no)
-	])
+	],
+	ac_cv_os_macosx=yes,
+	ac_cv_os_macosx=no,
+	ac_cv_os_macosx=no	dnl cross-compiling, assuming is not
+)])     
+AS_IF([test x$ac_cv_os_macosx = xyes],
+	[AC_DEFINE([HAVE_MACOSX], 1, [Is this a MacOS X system?])
+	 HAVE_MACOSX=yes
+	]
+)
 
 # Handle --enable-noselect-default
 AC_ARG_ENABLE(noselect-default,