non-posix code in sawfish configure.in

[Mark Diekhans <markd kermodei com>]

Hi Folks,
   
Some non-posix shell code has crept into sawfish configure.in.
Attached is a patch to fix it.

Cheers,
Mark

--- configure.in.ORG	2009-02-07 01:49:01.000000000 +0000
+++ configure.in	2009-02-07 01:52:40.000000000 +0000
@@ -103,16 +103,16 @@
 		  AC_DEFINE(X_DISPLAY_MISSING, 0, [Have x11])
 		  ,AC_MSG_ERROR([can not locate libX11]))
 
-X_LIBS+=" -lXext -lXrender"
+X_LIBS="${X_LIBS} -lXext -lXrender"
 
 X_EXTRA_LIBS=""
 
 PKG_CHECK_MODULES(libICE, ice >= 1.0
-		  ,X_EXTRA_LIBS+="-lICE "
+		  ,X_EXTRA_LIBS="${X_EXTRA_LIBS} -lICE"
 		  ,AC_MSG_ERROR([can't locate libICE]))
 
 PKG_CHECK_MODULES(libSM, sm >= 1.0
-		  ,X_EXTRA_LIBS+="-lSM "
+		  ,X_EXTRA_LIBS="${X_EXTRA_LIBS} -lSM"
 		  ,AC_MSG_ERROR([can't locate libSM]))
 
 X_SERVER="X.Org X11R7"
@@ -155,7 +155,7 @@
 dnl is X available?
 if test "${no_x}" != "yes"; then
   AC_DEFINE(HAVE_X11)
-  X_LIBS+=" -lXext -lXrender -lSM -lICE"
+  X_LIBS="${X_LIBS} -lXext -lXrender -lSM -lICE"
   X_EXTRA_LIBS=""
 else
   AC_MSG_ERROR([You need X11 for sawfish])
@@ -177,11 +177,11 @@
 		  ,AC_MSG_ERROR([can not locate pango]))
 
 PKG_CHECK_MODULES(PANGOX, pangox >= ${PANGO_MIN_VER}
-		  ,AC_DEFINE(HAVE_PANGO_X, 1, [Have pangox]) PANGO_MODULES+="pangox "
+		  ,AC_DEFINE(HAVE_PANGO_X, 1, [Have pangox]) PANGO_MODULES="${PANGO_MODULES} pangox"
 		  ,AC_MSG_WARN([pango x support not available]))
 
 PKG_CHECK_MODULES(PANGOXFT, pangoxft >= ${PANGO_MIN_VER}
-		  ,AC_DEFINE(HAVE_PANGO_XFT, 1, [Have pangoxft]) PANGO_MODULES+="pangoxft" have_pango_xft="yes" AC_SUBST(have_pango_xft)
+		  ,AC_DEFINE(HAVE_PANGO_XFT, 1, [Have pangoxft]) PANGO_MODULES="${PANGO_MODULES} pangoxft" have_pango_xft="yes" AC_SUBST(have_pango_xft)
 		  ,AC_MSG_WARN([pango xft support not available]))
 
 PANGO_LIBS=`pkg-config --libs $PANGO_MODULES`