[Qemu-devel] [PATCH v2 3/4] configure: Let SDL support be optional on OpenBSD

["Philippe Mathieu-Daudé" <philmd@redhat.com>]

Currently if we try to build QEMU on OpenBSD with SDL disabled, we get:

  $ ./configure --cc=x86_64-unknown-openbsd6.1-gcc-4.9.4 --python=python2.7 --disable-sdl

  ERROR: sdl not found or disabled, can not use sdl audio driver

Since SDL is not a requirement for OpenBSD, let it be optional.
If it is not found, or the user explicitly disable it, remove it
from the audio_drv_list.
If no audio backends are available, QEMU will fall back to the
null driver.
Instead of displaying nothing when audio_drv_list ends up empty,
display "none".

This does not change the default behavior:

  $ ./configure --cc=x86_64-unknown-openbsd6.1-gcc-4.9.4 --python=python2.7
  SDL support       yes (1.2.15)
  Audio drivers     sdl

  WARNING: Use of SDL 1.2 is deprecated and will be removed in
  WARNING: future releases. Please switch to using SDL 2.0

  GEN     config-host.h
  ...

but allows to build without SDL:

  $ ./configure --cc=x86_64-unknown-openbsd6.1-gcc-4.9.4 --python=python2.7 --disable-sdl
  WARN: sdl not found or disabled, can not use sdl audio driver
  SDL support       no
  Audio drivers     none
  GEN     config-host.h
  ...

Suggested-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
---
 configure | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/configure b/configure
index d50defceb7..fa444e9921 100755
--- a/configure
+++ b/configure
@@ -3379,7 +3379,8 @@ for drv in $audio_drv_list; do
 
     sdl)
     if test "$sdl" = "no"; then
-        error_exit "sdl not found or disabled, can not use sdl audio driver"
+        echo "WARN: sdl not found or disabled, can not use sdl audio driver"
+        audio_drv_list=$(echo "$audio_drv_list" | sed -e 's/sdl *//g')
     fi
     ;;
 
@@ -3408,6 +3409,9 @@ for drv in $audio_drv_list; do
     ;;
     esac
 done
+if test -z "$audio_drv_list"; then
+    audio_drv_list="none"
+fi
 
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 # BrlAPI probe
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2.20.1