diff -up guile-1.8.7/libguile/guile-snarf-docs.in.linemarkers guile-1.8.7/libguile/guile-snarf-docs.in
--- guile-1.8.7/libguile/guile-snarf-docs.in.linemarkers	2009-07-04 00:19:00.000000000 +0200
+++ guile-1.8.7/libguile/guile-snarf-docs.in	2009-11-19 17:58:03.000000000 +0100
@@ -23,4 +23,4 @@ bindir=`dirname $0`
 ## Let the user override the preprocessor autoconf found.
 test -n "${CPP+set}" || CPP="@CPP@"
 
-${CPP} -DSCM_MAGIC_SNARF_DOCS "$@"
+${CPP} -P -DSCM_MAGIC_SNARF_DOCS "$@"
diff -up guile-1.8.7/libguile/guile-snarf.in.linemarkers guile-1.8.7/libguile/guile-snarf.in
--- guile-1.8.7/libguile/guile-snarf.in.linemarkers	2009-11-19 16:31:46.000000000 +0100
+++ guile-1.8.7/libguile/guile-snarf.in	2009-11-19 18:10:09.000000000 +0100
@@ -49,7 +49,7 @@ modern_snarf ()                         
     ## Apparently, AIX's preprocessor is unhappy if you try to #include an
     ## empty file.
     echo "/* cpp arguments: $@ */" ;
-    ${cpp} -DSCM_MAGIC_SNARF_INITS -DSCM_MAGIC_SNARFER "$@" > ${temp} && cpp_ok_p=true
+    ${cpp} -P -DSCM_MAGIC_SNARF_INITS -DSCM_MAGIC_SNARFER "$@" > ${temp} && cpp_ok_p=true
     grep "^ *\^ *\^" ${temp} | sed -e "s/^ *\^ *\^//" -e "s/\^\ *:\ *\^.*/;/"
 }