diff --git a/configure b/configure
index e7c478f536..0d5ffc60aa 100755
--- a/configure
+++ b/configure
@@ -2962,14 +2962,16 @@ fi
 
 # auto-detect default include and library search paths
 gccout=`$TEST_COMPILER $SYSROOT_FLAG $TEST_COMPILER_CXXFLAGS -xc++ -E -v - < /dev/null 2>&1 > /dev/null`
+# extract from one line like 'LIBRARY_PATH=/one/path:/another/path:...'
 libdirs=`echo "$gccout" | sed -n -e 's/^LIBRARY_PATH=\(.*\)/\1/p'`
-DEFAULT_LIBDIRS=`IFS=${HOST_DIRLIST_SEP}; for i in $libdirs; do test -d "$i" && cd "$i" && pwd; done | sort -u`
+DEFAULT_LIBDIRS=`IFS=${HOST_DIRLIST_SEP}; for i in $libdirs; do test -d "$i" && cd "$i" && pwd; done`
+# extract from indented lines between '#include <...> search starts here:' and 'End of search list.'
 DEFAULT_INCDIRS=`echo "$gccout" | awk '
 /^End of search/ { yup=0 }
 / \(framework directory\)$/ { next }
 yup { print substr($0, 2) }
 /^\#include </ { yup=1 }
-' | sort -u`
+'`
 test -z "$DEFAULT_LIBDIRS" && DEFAULT_LIBDIRS="/lib
 /usr/lib"
 test -z "$DEFAULT_INCDIRS" && DEFAULT_INCDIRS="/usr/include