Fix trailing whitespace

configure.ac

@@ -1089,7 +1089,7 @@ AS_CASE([$host_os_gui], [cygwin* | mingw*], [
           AC_MSG_NOTICE([--enable-wayland: Pango libs and/or headers could not be found.])
           AC_MSG_ERROR([Aborting.])
       ])
-      
+
       dnl check for Xinerama, Xcursor, Xfixes, Xrender, Xregion.h
       AS_IF([test x$enable_x11 != xno], [
         xinerama_found=no
@@ -1112,7 +1112,7 @@ AS_CASE([$host_os_gui], [cygwin* | mingw*], [
           LIBS="$LIBS $($PKGCONFIG --libs xfixes)"
           xfixes_found=yes
         ])
-      
+
         xrender_found=no
         AS_IF([$PKGCONFIG --exists xrender], [
           AC_DEFINE(HAVE_XRENDER)