diff --git a/configure b/configure
index d2871e3..952bfc4 100755
--- a/configure
+++ b/configure
@@ -49,6 +49,9 @@ usage: $0 [OPTION..]
       --sharedir=DIR                Set share directory to DIR [PREFIX/share]
 $s
 
+      --add-deppath=DIR             Add DIR to the path to look for dependencies
+      --add-incpath=DIR             Add DIR to the path to look for dependencies' headers
+
       --no-shared                   Don't build shared libraries
       --no-static                   Don't build static libraries
       --no-doc                      Don't build documentation
@@ -78,6 +81,9 @@ libdir=
 incdir=
 sharedir=
 
+deppath=/lib:/usr/lib
+incpath=/include:/usr/include
+
 # this isn't quite right, since skalibs could be optional, but it'll do.
 has_skalibs=0
 if test -d meta/deps/skalibs; then has_skalibs=1; fi
@@ -121,13 +127,19 @@ for arg ; do
 
         --sysdeps=*) if test $has_skalibs -eq 1; then sysdeps=${arg#*=};
         else error 1 "invalid option '$arg'"; fi;;
+
         --no-shared) noshared=1 ;;
         --no-static) nostatic=1 ;;
         --no-doc|--no-docs|--no-documentation) nodoc=1 ;;
+
+        --add-deppath=*) deppath="${arg#*=}:$deppath" ;;
+        --add-incpath=*) incpath="${arg#*=}:$incpath" ;;
+
         --prefer-shared) prefer=shared ;;
         --prefer-static) prefer=static ;;
         --set-shared=*) eval "link${arg#*=}=1" ;;
         --set-static=*) eval "link${arg#*=}=2" ;;
+
         --with-*)    setoption $(expr substr "$arg"  8 ${#arg}) 0 ;;
         --without-*) setoption $(expr substr "$arg" 11 ${#arg}) 1 ;;
         --enable-*)  setoption $(expr substr "$arg" 10 ${#arg}) 0 ;;
@@ -139,18 +151,27 @@ for arg ; do
     esac
 done
 
+if test -n "$prefix"; then
+    deppath="$prefix/lib:$deppath"
+    incpath="$prefix/include:$incpath"
+fi
 if test -z "$prefix"; then prefix="/usr"; fi
 if test -z "$bindir"; then bindir="$prefix/bin"; fi
 if test -z "$libdir"; then libdir="$prefix/lib"; fi
 if test -z "$incdir"; then incdir="$prefix/include"; fi
 if test -z "$sharedir"; then sharedir="$prefix/share"; fi
-if test -z "$sysdeps"; then sysdeps="$libdir/skalibs/sysdeps"; fi
 
+deppath="$(echo $deppath | sed 's/\/\+/\//g')"
+incpath="$(echo $incpath | sed 's/\/\+/\//g')"
 bindir="$(echo $bindir | sed 's/\/\+/\//g')"
 libdir="$(echo $libdir | sed 's/\/\+/\//g')"
 incdir="$(echo $incdir | sed 's/\/\+/\//g')"
 sharedir="$(echo $sharedir | sed 's/\/\+/\//g')"
-sysdeps="$(echo $sysdeps | sed 's/\/\+/\//g')"
+
+ndeppath=$(echo $deppath | tr -dc : | wc -c)
+nincpath=$(echo $incpath | tr -dc : | wc -c)
+ndeppath=$(( ndeppath + 1 ))
+nincpath=$(( nincpath + 1 ))
 
 # pass 2, to be able to use state of other options as selection
 setoptionsdefault
@@ -161,29 +182,47 @@ procdep_real()
 {
     local depdir="$1"
     local intdir="$2"
-    local libdir="$3"
-    local incdir="$4"
 
     local depname="${depdir##*/}"
-    local libname="$(cat "$depdir/library" 2>/dev/null)"
-    if test -z "$libname"; then libname="$depname"; fi
 
     # internal or not?
     local isint=0
     if test -d "$intdir/$depname"; then isint=1; fi
 
-    local d
+    # is it lila?
+    local islila=0
+    if ! test -e "$depdir/get_version"; then islila=1; fi
 
-    # can we find it?
     if test $isint -eq 1; then
-        d="$intdir/$depname"
+        procdep_search "$depname" "$depdir" "$intdir" $isint $islila "$intdir/$depname"
     else
-        d="$libdir"
+        local i=1
+        local s
+
+        while test $i -le $ndeppath; do
+            s="$(echo $deppath | cut -d: -f$i)"
+            s="$(procdep_search "$depname" "$depdir" "$intdir" $isint $islila "$s")"
+            if ! test "$(expr substr "$s" 3 8)" = "NOTFOUND"; then
+                echo $s
+                return
+            fi
+            i=$(( ++i ))
+        done
+        echo "$isint NOTFOUND"
     fi
+}
 
-    # is it lila?
-    local islila=0
-    if ! test -e "$depdir/get_version"; then islila=1; fi
+procdep_search()
+{
+    local depname="$1"
+    local depdir="$2"
+    local intdir="$3"
+    local isint="$4"
+    local islila="$5"
+    local libdir="$6"
+    local d="$libdir"
+
+    local incdir
 
     # look for it
     local vpath
@@ -196,6 +235,7 @@ procdep_real()
             if test $isint -eq 1; then d="$d/build"; fi
             if ! test -d "$d/comain/$depname"; then
                 echo $isint NOTFOUND
+                return
             fi
         else
             r=0
@@ -205,20 +245,41 @@ procdep_real()
             if test $? -eq 0; then r=1; fi
             if test $r -eq 0; then
                 echo $isint NOTFOUND
+                return
             fi
 
-            r=0
+            local p
+            local n
             if test $isint -eq 1; then
-                inc="$d"
+                n=1
+                p="$d"
             else
-                inc="$incdir"
+                n=$nincpath
+                p="$incpath"
             fi
-            inc="$inc/$($depdir/is_found $isint include "$inc" 2>/dev/null)"
-            if test $? -eq 0; then r=1; fi
+
+            local i=1
+            local s
+
+            r=0
+            while test $i -le $n; do
+                s="$(echo $p | cut -d: -f$i)"
+                inc="$($depdir/is_found $isint include "$s" 2>/dev/null)"
+                if test $? -eq 0; then
+                    r=1
+                    break
+                fi
+                i=$(( ++i ))
+            done
             if test $r -eq 0; then
                 echo $isint INCNOTFOUND
+                return
+            fi
+            if test "$inc" = "-"; then
+                incdir=
+            else
+                incdir="$s/$inc"
             fi
-            incdir="$inc"
         fi
     fi
 
@@ -277,26 +338,18 @@ procdep_real()
         cflagsA="$(cat "$d/cflags.static" 2>/dev/null)"
         cppflags="$(cat "$d/cppflags" 2>/dev/null)"
         cppflagsA="$(cat "$d/cppflags.static" 2>/dev/null)"
-        vpath="$libdir"
-        vpathA="$libdir"
     else
         libs="$("$depdir/get_libs" shared $isint "$intdir/$depname" "$libdir" "$incdir" 2>/dev/null)"
         libsA="$("$depdir/get_libs" static $isint "$intdir/$depname" "$libdir" "$incdir" 2>/dev/null)"
+        inc="$incdir"
         ldflags="$("$depdir/get_ldflags" shared $isint "$intdir/$depname" "$libdir" "$incdir" 2>/dev/null)"
         ldflagsA="$("$depdir/get_ldflags" static $isint "$intdir/$depname" "$libdir" "$incdir" 2>/dev/null)"
         cflags="$("$depdir/get_cflags" shared $isint "$intdir/$depname" "$libdir" "$incdir" 2>/dev/null)"
         cflagsA="$("$depdir/get_cflags" static $isint "$intdir/$depname" "$libdir" "$incdir" 2>/dev/null)"
         cppflags="$("$depdir/get_cppflags" shared $isint "$intdir/$depname" "$libdir" "$incdir" 2>/dev/null)"
         cppflagsA="$("$depdir/get_cppflags" static $isint "$intdir/$depname" "$libdir" "$incdir" 2>/dev/null)"
-        vpath="$("$depdir/get_vpath" shared "$libdir" 2>/dev/null)"
-        vpathA="$("$depdir/get_vpath" static "$libdir" 2>/dev/null)"
     fi
-    if test $isint -eq 1; then
-        d="$intdir/$depname"
-        vpath="$d"
-        vpathA="$d"
-    fi
-    cppflags="-isystem $inc $cppflags"
+    test -n "$inc" && cppflags="-isystem $inc $cppflags"
 
     # lila: dependencies?
     if test $islila -eq 1; then
@@ -316,7 +369,7 @@ procdep_real()
                 local err
                 local i=0
                 mkfifo $tmp
-                procdep_real "$d" "$intdir" "$libdir" "$incdir" > "$tmp" &
+                procdep_real "$d" "$intdir" > "$tmp" &
                 while IFS= read -r arg; do
                     if test $i -ne 1; then
                         i=1
@@ -397,8 +450,6 @@ procdep()
     # a different dirname (inside $incdir) might be specified
     if test -e "$dep/include"; then path="$(cat $dep/include)"; fi
     local path="$incdir/$path"
-    local library="$depname"
-    if test -e "$dep/library"; then library="$(cat $dep/library)"; fi
     local internal=0
     local found=0
     local depdir=
@@ -425,7 +476,7 @@ procdep()
     local s
     local i=0
     mkfifo $tmp
-    procdep_real "$dep" "deps" "$libdir" "$incdir" > "$tmp" &
+    procdep_real "$dep" "deps" > "$tmp" &
     while IFS= read -r arg; do
         if test $i -ne 1; then
             i=1
@@ -540,8 +591,13 @@ procdep()
         VPATHS="$VPATHS
 $(mkvpath $link "$vpath" $deplibs)"
 
-        if test $internal -eq 1 && test $depname = "skalibs"; then
-            sysdeps="$depdir/sysdeps.cfg"
+        if test $depname = "skalibs"; then
+            if test $internal -eq 1; then
+                sysdeps="$depdir/sysdeps.cfg"
+            else
+                if test -z "$sysdeps"; then sysdeps="$(echo $vpath)/skalibs/sysdeps"; fi
+                sysdeps="$(echo $sysdeps | sed 's/\/\+/\//g')"
+            fi
         fi
     fi
 }