configure: kill off NEED_NONNULL_WINSYS

The variable was unused and gave false information. The need for nonnull
winsys currently does not relate as it used to. Nowadays one can mix and
match more freely with plenty of winsys' to make your head spin.

Signed-off-by: Emil Velikov <emil.l.velikov@gmail.com>
diff --git a/configure.ac b/configure.ac
index 15e0351..c2735c2 100644
--- a/configure.ac
+++ b/configure.ac
@@ -1820,27 +1820,26 @@
 dnl Gallium helper functions
 dnl
 gallium_check_st() {
-    if test "x$NEED_NONNULL_WINSYS" = xyes; then
-         if test "x$have_libdrm" != xyes; then
-            AC_MSG_ERROR([DRI or Xorg DDX requires libdrm >= $LIBDRM_REQUIRED])
-         fi
-         GALLIUM_WINSYS_DIRS="$GALLIUM_WINSYS_DIRS $1"
+    if test "x$have_libdrm" != xyes; then
+       AC_MSG_ERROR([$1 requires libdrm >= $LIBDRM_REQUIRED])
     fi
-    if test "x$enable_dri" = xyes && test -n "$2"; then
-         GALLIUM_TARGET_DIRS="$GALLIUM_TARGET_DIRS $2"
-    fi
-    if test "x$enable_xa" = xyes && test -n "$3"; then
+    GALLIUM_WINSYS_DIRS="$GALLIUM_WINSYS_DIRS $2"
+
+    if test "x$enable_dri" = xyes && test -n "$3"; then
          GALLIUM_TARGET_DIRS="$GALLIUM_TARGET_DIRS $3"
     fi
-    if test "x$enable_xvmc" = xyes && test -n "$4"; then
+    if test "x$enable_xa" = xyes && test -n "$4"; then
          GALLIUM_TARGET_DIRS="$GALLIUM_TARGET_DIRS $4"
     fi
-    if test "x$enable_vdpau" = xyes && test -n "$5"; then
+    if test "x$enable_xvmc" = xyes && test -n "$5"; then
          GALLIUM_TARGET_DIRS="$GALLIUM_TARGET_DIRS $5"
     fi
-    if test "x$enable_omx" = xyes && test "x$6" != x; then
+    if test "x$enable_vdpau" = xyes && test -n "$6"; then
          GALLIUM_TARGET_DIRS="$GALLIUM_TARGET_DIRS $6"
     fi
+    if test "x$enable_omx" = xyes && test "x$7" != x; then
+         GALLIUM_TARGET_DIRS="$GALLIUM_TARGET_DIRS $7"
+    fi
 }
 
 gallium_require_llvm() {
@@ -1898,13 +1897,6 @@
                                  [AC_MSG_ERROR([$1 requires libelf when using LLVM])])
 }
 
-dnl Gallium drivers
-if test "x$enable_dri" = xyes -o "x$enable_xa" = xyes -o \
-        "x$enable_xvmc" = xyes -o "x$enable_vdpau" = xyes; then
-    NEED_NONNULL_WINSYS=yes
-fi
-AM_CONDITIONAL(NEED_NONNULL_WINSYS, test "x$NEED_NONNULL_WINSYS" = xyes)
-
 dnl Duplicates in GALLIUM_DRIVERS_DIRS are removed by sorting it after this block
 if test -n "$with_gallium_drivers"; then
     gallium_drivers=`IFS=', '; echo $with_gallium_drivers`
@@ -1912,26 +1904,23 @@
         case "x$driver" in
         xsvga)
             HAVE_GALLIUM_SVGA=yes
-            if test "x$have_libdrm" != xyes; then
-                AC_MSG_ERROR([Building svga requires libdrm >= $LIBDRM_REQUIRED])
-            fi
             GALLIUM_DRIVERS_DIRS="$GALLIUM_DRIVERS_DIRS svga softpipe"
             gallium_require_drm_loader
-            gallium_check_st "svga/drm" "dri/vmwgfx" "xa/vmwgfx"
+            gallium_check_st "svga" "svga/drm" "dri/vmwgfx" "xa/vmwgfx"
             ;;
         xi915)
             HAVE_GALLIUM_I915=yes
             PKG_CHECK_MODULES([INTEL], [libdrm_intel >= $LIBDRM_INTEL_REQUIRED])
             gallium_require_drm_loader
             GALLIUM_DRIVERS_DIRS="$GALLIUM_DRIVERS_DIRS i915"
-            gallium_check_st "i915/drm" "dri/i915" "xa/i915"
+            gallium_check_st "Gallium i915" "i915/drm" "dri/i915" "xa/i915"
             ;;
         xilo)
             HAVE_GALLIUM_ILO=yes
             PKG_CHECK_MODULES([INTEL], [libdrm_intel >= $LIBDRM_INTEL_REQUIRED])
             gallium_require_drm_loader
             GALLIUM_DRIVERS_DIRS="$GALLIUM_DRIVERS_DIRS ilo"
-            gallium_check_st "intel/drm" "dri/ilo" "xa/ilo"
+            gallium_check_st "Gallium i965/ilo" "intel/drm" "dri/ilo" "xa/ilo"
             ;;
         xr300)
             HAVE_GALLIUM_R300=yes
@@ -1939,7 +1928,7 @@
             gallium_require_drm_loader
             gallium_require_llvm "Gallium R300"
             GALLIUM_DRIVERS_DIRS="$GALLIUM_DRIVERS_DIRS r300"
-            gallium_check_st "radeon/drm" "dri/r300"
+            gallium_check_st "Gallium R300" "radeon/drm" "dri/r300"
             ;;
         xr600)
             HAVE_GALLIUM_R600=yes
@@ -1956,7 +1945,7 @@
             if test "x$enable_opencl" = xyes; then
                 LLVM_COMPONENTS="${LLVM_COMPONENTS} bitreader asmparser"
             fi
-            gallium_check_st "radeon/drm" "dri/r600" "" "xvmc/r600" "vdpau/r600" "omx/r600"
+            gallium_check_st "Gallium R600" "radeon/drm" "dri/r600" "" "xvmc/r600" "vdpau/r600" "omx/r600"
             ;;
         xradeonsi)
             HAVE_GALLIUM_RADEONSI=yes
@@ -1965,21 +1954,21 @@
             GALLIUM_DRIVERS_DIRS="$GALLIUM_DRIVERS_DIRS radeonsi"
             radeon_llvm_check "radeonsi"
             require_egl_drm "radeonsi"
-            gallium_check_st "radeon/drm" "dri/radeonsi" "" "" "vdpau/radeonsi" "omx/radeonsi"
+            gallium_check_st "radeonsi" "radeon/drm" "dri/radeonsi" "" "" "vdpau/radeonsi" "omx/radeonsi"
             ;;
         xnouveau)
             HAVE_GALLIUM_NOUVEAU=yes
             PKG_CHECK_MODULES([NOUVEAU], [libdrm_nouveau >= $LIBDRM_NOUVEAU_REQUIRED])
             gallium_require_drm_loader
             GALLIUM_DRIVERS_DIRS="$GALLIUM_DRIVERS_DIRS nouveau"
-            gallium_check_st "nouveau/drm" "dri/nouveau" "xa/nouveau" "xvmc/nouveau" "vdpau/nouveau" "omx/nouveau"
+            gallium_check_st "nouveau" "nouveau/drm" "dri/nouveau" "xa/nouveau" "xvmc/nouveau" "vdpau/nouveau" "omx/nouveau"
             ;;
         xfreedreno)
             HAVE_GALLIUM_FREEDRENO=yes
             PKG_CHECK_MODULES([FREEDRENO], [libdrm_freedreno >= $LIBDRM_FREEDRENO_REQUIRED])
             gallium_require_drm_loader
             GALLIUM_DRIVERS_DIRS="$GALLIUM_DRIVERS_DIRS freedreno"
-            gallium_check_st "freedreno/drm" "dri/freedreno" "xa/freedreno" "" ""
+            gallium_check_st "freedreno" "freedreno/drm" "dri/freedreno" "xa/freedreno" "" ""
             ;;
         xswrast)
             HAVE_GALLIUM_SOFTPIPE=yes
@@ -2001,7 +1990,7 @@
             HAVE_GALLIUM_VC4=yes
             gallium_require_drm_loader
             GALLIUM_DRIVERS_DIRS="$GALLIUM_DRIVERS_DIRS vc4"
-            gallium_check_st "vc4/drm" "dri-vc4" "" "" ""
+            gallium_check_st "vc4" "vc4/drm" "dri-vc4" "" "" ""
 
             case "$host_cpu" in
                 i?86 | x86_64 | amd64)
@@ -2123,8 +2112,7 @@
 AM_CONDITIONAL(HAVE_RADEON_DRI, test x$HAVE_RADEON_DRI = xyes)
 AM_CONDITIONAL(HAVE_SWRAST_DRI, test x$HAVE_SWRAST_DRI = xyes)
 
-AM_CONDITIONAL(NEED_RADEON_DRM_WINSYS, test "x$NEED_NONNULL_WINSYS" = xyes -a \
-                                            "x$HAVE_GALLIUM_R300" = xyes -o \
+AM_CONDITIONAL(NEED_RADEON_DRM_WINSYS, test "x$HAVE_GALLIUM_R300" = xyes -o \
                                             "x$HAVE_GALLIUM_R600" = xyes -o \
                                             "x$HAVE_GALLIUM_RADEONSI" = xyes)
 AM_CONDITIONAL(NEED_WINSYS_WRAPPER, test "x$HAVE_GALLIUM_I915" = xyes -o \