--- orig/m4/boost.m4	2008-01-22 18:46:39.000000000 -0500
+++ new/m4/boost.m4	2008-01-26 01:53:00.000000000 -0500
@@ -227,10 +227,15 @@
     mt* | mt-*) boost_mt=-mt; boost_rtopt=`expr "X$2" : 'Xmt-*\(.*\)'`;; #(
     *) boost_mt=; boost_rtopt=$2;;
   esac
-  # If the PREFERRED-RT-OPT are not empty, prepend a `-'.
+  # Find the proper debug variant depending on what we've been asked to find.
   case $boost_rtopt in #(
-    *[[a-z0-9A-Z]]*) boost_rtopt="-$boost_rtopt";;
+    *d*) boost_rt_d="-$boost_rtopt";; #(
+    *[[sgpn]]*) # Insert the `d' at the right place (in between `sg' and `pn')
+      boost_rt_d=`echo "$boost_rtopt" | sed 's/\(s*g*\)\(p*n*\)/-\1d\2/'`;; #(
+    *) boost_rt_d='-d';;
   esac
+  # If the PREFERRED-RT-OPT are not empty, prepend a `-'.
+  test -n "$boost_rtopt" && boost_rtopt="-$boost_rtopt"
   $boost_guess_use_mt && boost_mt=-mt
   # Look for the abs path the static archive.
   # $libext is computed by Libtool but let's make sure it's non empty.
@@ -266,12 +271,11 @@
 for boost_tag_ in -$boost_cv_lib_tag ''; do
 for boost_ver_ in -$boost_cv_lib_version ''; do
 for boost_mt_ in $boost_mt -mt ''; do
-for boost_rtopt_ in $boost_rtopt '' -d; do
+for boost_rtopt_ in $boost_rtopt $boost_rt_d; do
   for boost_lib in \
     boost_$1$boost_tag_$boost_mt_$boost_rtopt_$boost_ver_ \
-    boost_$1$boost_tag_$boost_mt_$boost_ver_ \
     boost_$1$boost_tag_$boost_rtopt_$boost_ver_ \
-    boost_$1$boost_tag_$boost_mt_ \
+    boost_$1$boost_tag_$boost_mt_$boost_ver_ \
     boost_$1$boost_tag_$boost_ver_
   do
     # Avoid testing twice the same lib