Strip versioning components from *HOST for Darwin and Solaris

--- aclocal.m4
+++ aclocal.m4
@@ -1358,6 +1358,12 @@
   freebsd*)
     $2="freebsd"
     ;;
+  darwin*)
+    $2="darwin"
+	;;
+  solaris2.*)
+    $2="solaris2"
+	;;
   *)
     echo "Unknown OS $1"
     exit 1
--- configure.ac
+++ configure.ac
@@ -227,6 +227,7 @@
 fi
 build=`echo "$build" | sed -e 's/linux-gnu/linux/' -e 's/-pc-/-unknown-/' -e 's/-gentoo-/-unknown-/' -e 's/freebsd.*$/freebsd/'`
 [build=`echo "$build" | sed -e 's/i[4-6]86/i386/'`] # escaping square bracket
+build=`echo "$build" | sed -e 's/-darwin.*$/-darwin/' -e 's/-solaris2.*$/-solaris/'`
 
 # We have to run these unconditionally, but we may discard their
 # results in the following code
@@ -262,6 +263,7 @@
 fi
 host=`echo "$host" | sed -e 's/linux-gnu/linux/' -e 's/-pc-/-unknown-/' -e 's/-gentoo-/-unknown-/' -e 's/freebsd.*$/freebsd/'`
 [host=`echo "$host" | sed -e 's/i[4-6]86/i386/'`] # escaping square bracket
+host=`echo "$host" | sed -e 's/-darwin.*$/-darwin/' -e 's/-solaris2.*$/-solaris/'`
 
 if test "$host_alias" = ""
 then
@@ -284,6 +286,7 @@
 fi
 target=`echo "$target" | sed -e 's/linux-gnu/linux/' -e 's/-pc-/-unknown-/' -e 's/-gentoo-/-unknown-/' -e 's/freebsd.*$/freebsd/'`
 [target=`echo "$target" | sed -e 's/i[4-6]86/i386/'`] # escaping square bracket
+target=`echo "$target" | sed -e 's/-darwin.*$/-darwin/' -e 's/-solaris2.*$/-solaris/'`
 
 if test "$target_alias" = ""
 then