configure: avoid constantly building megadrivers 'core'

The issue is caused by a thinko that an empty string will be
considered of zero length by 'test'. This is not the case,
thus we were building the 'core' of megadrivers even when no
classic drivers were built.

Signed-off-by: Emil Velikov <emil.l.velikov@gmail.com>

diff --git a/configure.ac b/configure.ac
index 0e0fd1820f415f5298be947c1598a38b91d37340..1688aae05c9a3fce7778c8a040c6c7b802482578 100644 (file)
--- a/configure.ac
+++ b/configure.ac
@@ -965,6 +965,9 @@ if test "x$with_dri_drivers" = xauto; then
         with_dri_drivers="no"
     fi
 fi
+if test "x$with_dri_drivers" = xno; then
+    with_dri_drivers=''
+fi
 
 dnl If $with_dri_drivers is yes, drivers will be added through
 dnl platform checks. Set DEFINES and LIB_DEPS
@@ -1043,9 +1046,9 @@ fi
 AC_SUBST([DRI_LIB_DEPS])
 AC_SUBST([GALLIUM_DRI_LIB_DEPS])
 
-DRI_DIRS=""
-dnl Duplicates in DRI_DIRS are removed by sorting it after this block
-if test "x$with_dri_drivers" != xno; then
+DRI_DIRS=''
+dnl Duplicates in DRI_DIRS are removed by sorting it at the end of this block
+if test -n "$with_dri_drivers"; then
     if test "x$enable_opengl" != xyes; then
         AC_MSG_ERROR([--with-dri-drivers requires OpenGL])
     fi
@@ -1082,8 +1085,8 @@ if test "x$with_dri_drivers" != xno; then
             ;;
         esac
     done
+    DRI_DIRS=`echo $DRI_DIRS|tr " " "\n"|sort -u|tr "\n" " "`
 fi
-DRI_DIRS=`echo $DRI_DIRS|tr " " "\n"|sort -u|tr "\n" " "`
 
 AM_CONDITIONAL(NEED_MEGADRIVER, test -n "$DRI_DIRS")
 AM_CONDITIONAL(NEED_LIBMESA, test "x$enable_xlib_glx" = xyes -o \