Load libcapi20.so.* dynamically on demand.

diff --git a/configure.ac b/configure.ac
index ff7e272..bc69f43 100644
--- a/configure.ac
+++ b/configure.ac
@@ -700,7 +700,6 @@
 	AC_CHECK_HEADERS(linux/capi.h,[
 		AC_CHECK_LIB(capi20,capi20_register,[
 			AC_DEFINE(HAVE_CAPI4LINUX,1,[Define if you have capi4linux libs and headers])
-			AC_SUBST(CAPI4LINUXLIBS,"-lcapi20")
 		])
 	])
 ])
@@ -1106,6 +1105,7 @@
   WINE_GET_SONAME(ungif,DGifOpen)
   WINE_GET_SONAME(gif,DGifOpen)
   WINE_GET_SONAME(lcms,cmsOpenProfileFromFile)
+  WINE_GET_SONAME(capi20,capi20_isinstalled)
 fi