Update OpenAL-soft to 1.23.1-bc7cb17.

libs/openal-soft/docs/env-vars.txt

@@ -58,6 +58,12 @@ between 0 and 180 degrees, instead of the expected range of 0 to 360 degrees.
 Setting this to "true" or "1" restores the old buggy behavior, for apps that
 were written to expect the incorrect range.
 
+__ALSOFT_ENABLE_SUB_DATA_EXT
+The more widely used AL_EXT_SOURCE_RADIUS extension is incompatible with the
+now-defunct AL_SOFT_buffer_sub_data extension. Setting this to "true" or "1"
+restores the AL_SOFT_buffer_sub_data extension for apps that require it,
+disabling AL_EXT_SOURCE_RADIUS.
+
 __ALSOFT_REVERSE_Z
 Applications that don't natively use OpenAL's coordinate system have to convert
 to it before passing in 3D coordinates. Depending on how exactly this is done,
@@ -72,6 +78,15 @@ Same as for __ALSOFT_REVERSE_Z, but for Y (up/down) panning.
 __ALSOFT_REVERSE_X
 Same as for __ALSOFT_REVERSE_Z, but for X (left/right) panning.
 
+__ALSOFT_DEFAULT_ERROR
+Applications that erroneously call alGetError prior to setting a context as
+current may not like that OpenAL Soft returns 0xA004 (AL_INVALID_OPERATION),
+indicating that the call could not be executed as there's no context to get the
+error value from. This can be set to 0 (AL_NO_ERROR) to let such apps pass the
+check despite the problem. Other applications, however, may see AL_NO_ERROR
+returned and assume any previous AL calls succeeded when they actually failed,
+so this should only be set when necessary.
+
 __ALSOFT_SUSPEND_CONTEXT
 Due to the OpenAL spec not being very clear about them, behavior of the
 alcSuspendContext and alcProcessContext methods has varied, and because of