fix autogen.sh so users don't have to set PKG_CONFIG_PATH and similar…

… *PATH's

autogen.sh

@@ -1,13 +1,35 @@
 #! /bin/sh
 
-# Append any prefix from PKG_CONFIG_PATH to ACLOCAL_PATH
-OLDIFS=IFS
-IFS=':'
-for dir in $PKG_CONFIG_PATH; do
-    acdir="$dir/../../share/aclocal"
-    [ -x "$acdir" ] && ACLOCAL_PATH="${ACLOCAL_PATH}:$acdir"
+# If the user specified a --prefix, take that, otherwise /usr/local/
+# is the default.
+PREFIX=/usr/local
+prefixnext=false
+for i in "$@"; do
+    case $i in
+        --prefix=*)		# equals separated:
+	    PREFIX="${i#*=}"
+	    ;;
+        --prefix)		# space separated:
+	    prefixnext=true
+	    ;;
+        *)
+	    $prefixnext && PREFIX="$i" && prefixnext=false
+	    ;;
+    esac
 done
-IFS=OLDIFS
+
+# Set the paths needed by libtool/pkg-config/aclocal etc. By inferring
+# them based on --prefix , users don't have to edit ~/.bashrc. We only
+# append, so if a user has some other preference, that will override.
+PATH="${PATH}:/usr/local/bin"
+export PATH
+LD_LIBRARY_PATH="${LD_LIBRARY_PATH}:${PREFIX}/lib"
+export LD_LIBRARY_PATH
+PKG_CONFIG_PATH="${PKG_CONFIG_PATH}:${PREFIX}/lib/pkgconfig"
+export PKG_CONFIG_PATH
+ACLOCAL_PATH="${ACLOCAL_PATH}:${PREFIX}/share/aclocal"
 export ACLOCAL_PATH
 
+
+# Pass on all args to configure
 autoreconf -fi && ./configure "$@"