diff --git a/common/configure.ac b/common/configure.ac
index 198d664..f0b8a8a 100644
--- a/common/configure.ac
+++ b/common/configure.ac
@@ -10,6 +10,9 @@
 AC_PROG_LIBTOOL
 AC_LANG([C++])
 
+AC_CONFIG_HEADERS([common-config.h])
+CPPFLAGS="-DHAVE_COMMON_CONFIG_H $CPPFLAGS"
+
 case "`(uname -sr) 2>/dev/null`" in
 "SunOS 5"*)
   SOLARIS=yes
@@ -42,13 +45,13 @@
 dnl Checks for IRIX-specific Compression Library.
 AC_SEARCH_LIBS([clQuerySchemeFromName])
 AC_CHECK_LIB(cl, clQuerySchemeFromName,
-  [AC_DEFINE(HAVE_CL)
+  [AC_DEFINE([HAVE_CL], 1, [Define if you have IRIX compression library])
   IRIX_COMPRESS=yes])
 AM_CONDITIONAL([IRIX_COMPRESS], [ test "x$IRIX_COMPRESS" = xyes ])
 
 dnl Checks for IRIX-specific Digital Media libraries.
 AC_CHECK_LIB(dmedia, dmICCreate,
-  [AC_DEFINE(HAVE_DMEDIA)
+  [AC_DEFINE(HAVE_DMEDIA, 1, [Define if you have IRIX Digital Media library])
   IRIX_MEDIA=yes])
 AM_CONDITIONAL([IRIX_MEDIA], [ test "x$IRIX_MEDIA" = xyes ])
 
@@ -96,28 +99,11 @@
 AC_SUBST(JPEG_INCLUDE)
 AC_SUBST(JPEG_LIB)
 
-AC_CHECK_FUNC(vsnprintf,VSNPRINTF_DEFINE='-DHAVE_VSNPRINTF',VSNPRINTF_DEFINE=)
-AC_SUBST(VSNPRINTF_DEFINE)
+AC_CHECK_FUNCS_ONCE([vsnprintf strcasecmp strncasecmp])
 
-AC_CHECK_FUNC(strcasecmp,STRCASECMP_DEFINE='-DHAVE_STRCASECMP',
-  STRCASECMP_DEFINE=)
-AC_SUBST(STRCASECMP_DEFINE)
-
-AC_CHECK_FUNC(strncasecmp,STRNCASECMP_DEFINE='-DHAVE_STRNCASECMP',
-  STRNCASECMP_DEFINE=)
-AC_SUBST(STRNCASECMP_DEFINE)
-
-AC_MSG_CHECKING(for socklen_t)
-AC_TRY_COMPILE(
-[#include <sys/types.h>
- #include <sys/socket.h>],
-[socklen_t x;
-accept(0, 0, &x);],
-AC_MSG_RESULT(yes)
-SOCKLEN_T_DEFINE='-DVNC_SOCKLEN_T=socklen_t',
-AC_MSG_RESULT(using int)
-SOCKLEN_T_DEFINE='-DVNC_SOCKLEN_T=int')
-AC_SUBST(SOCKLEN_T_DEFINE)
+AC_CHECK_TYPES([socklen_t],
+	[AC_DEFINE([VNC_SOCKLEN_T], [socklen_t], [Use correct size])],
+	[AC_DEFINE([VNC_SOCKLEN_T], [int])])
 
 AC_OUTPUT([Makefile
 	   rdr/Makefile
diff --git a/common/network/Makefile.am b/common/network/Makefile.am
index 61d276b..c4bad93 100644
--- a/common/network/Makefile.am
+++ b/common/network/Makefile.am
@@ -4,5 +4,5 @@
 
 libnetwork_la_SOURCES = $(HDRS) TcpSocket.cxx
 
-libnetwork_la_CPPFLAGS = -I$(top_srcdir) @SOCKLEN_T_DEFINE@
+libnetwork_la_CPPFLAGS = -I$(top_srcdir)
 
diff --git a/common/network/TcpSocket.cxx b/common/network/TcpSocket.cxx
index 5dd2428..777627b 100644
--- a/common/network/TcpSocket.cxx
+++ b/common/network/TcpSocket.cxx
@@ -16,6 +16,10 @@
  * USA.
  */
 
+#ifdef HAVE_COMMON_CONFIG_H
+#include <common-config.h>
+#endif
+
 #ifdef WIN32
 //#include <io.h>
 #include <winsock2.h>
@@ -42,10 +46,6 @@
 #include <rfb/util.h>
 #include <rfb/LogWriter.h>
 
-#ifndef VNC_SOCKLEN_T
-#define VNC_SOCKLEN_T int
-#endif
-
 #ifndef INADDR_NONE
 #define INADDR_NONE ((unsigned long)-1)
 #endif
diff --git a/common/rfb/JpegEncoder.cxx b/common/rfb/JpegEncoder.cxx
index 7129192..2c47a60 100644
--- a/common/rfb/JpegEncoder.cxx
+++ b/common/rfb/JpegEncoder.cxx
@@ -16,6 +16,10 @@
  * USA.
  */
 
+#ifdef HAVE_COMMON_CONFIG_H
+#include <common-config.h>
+#endif
+
 #include <rfb/JpegEncoder.h>
 #include <rdr/OutStream.h>
 #include <rdr/Exception.h>
diff --git a/common/rfb/Logger.cxx b/common/rfb/Logger.cxx
index 6b9cfa3..8c90906 100644
--- a/common/rfb/Logger.cxx
+++ b/common/rfb/Logger.cxx
@@ -18,6 +18,10 @@
 
 // -=- Logger.cxx - support for the Logger and LogWriter classes
 
+#ifdef HAVE_COMMON_CONFIG_H
+#include <common-config.h>
+#endif
+
 #include <stdarg.h>
 #include <stdio.h>
 #include <string.h>
diff --git a/common/rfb/Makefile.am b/common/rfb/Makefile.am
index 30c06d7..f2106d1 100644
--- a/common/rfb/Makefile.am
+++ b/common/rfb/Makefile.am
@@ -53,8 +53,7 @@
 librfb_la_SOURCES += IrixDMJpegCompressor.cxx IrixDMIC_RawToJpeg.cxx
 endif
 
-librfb_la_CPPFLAGS = -I$(top_srcdir) @JPEG_INCLUDE@ @VSNPRINTF_DEFINE@ \
-	@STRCASECMP_DEFINE@ @STRNCASECMP_DEFINE@
+librfb_la_CPPFLAGS = -I$(top_srcdir) @JPEG_INCLUDE@
 
 librfb_la_LIBADD = @JPEG_LIB@
 
diff --git a/common/rfb/util.cxx b/common/rfb/util.cxx
index 5745432..7950a1d 100644
--- a/common/rfb/util.cxx
+++ b/common/rfb/util.cxx
@@ -30,6 +30,10 @@
  * is provided ``as is'' without express or implied warranty.
  */
 
+#ifndef HAVE_COMMON_CONFIG_H
+#include <common-config.h>
+#endif
+
 #include <rfb/util.h>
 
 // Provide strcasecmp() and/or strncasecmp() if absent on this system.
diff --git a/common/rfb/util.h b/common/rfb/util.h
index fa205f0..933df52 100644
--- a/common/rfb/util.h
+++ b/common/rfb/util.h
@@ -23,6 +23,10 @@
 #ifndef __RFB_UTIL_H__
 #define __RFB_UTIL_H__
 
+#ifdef HAVE_COMMON_CONFIG_H
+#include <common-config.h>
+#endif
+
 #include <limits.h>
 #include <string.h>