SDL's alsa uses snd_pcm_recover() which has been available
only since alsa-lib-1.0.11. The following patches fix the
configury and cmake checks for both SDL2 and also for SDL1.2.


Patch for SDL2 (current hg):

diff -r 7d5a98aac368 cmake/sdlchecks.cmake
--- a/cmake/sdlchecks.cmake	Thu Jun 25 07:17:08 2015 -0700
+++ b/cmake/sdlchecks.cmake	Sun Jun 28 00:55:51 2015 +0300
@@ -105,7 +105,9 @@
   if(ALSA)
     CHECK_INCLUDE_FILE(alsa/asoundlib.h HAVE_ASOUNDLIB_H)
     if(HAVE_ASOUNDLIB_H)
-      CHECK_LIBRARY_EXISTS(asound snd_pcm_open "" HAVE_LIBASOUND)
+      CHECK_LIBRARY_EXISTS(asound snd_pcm_recover "" HAVE_LIBASOUND)
+    endif()
+    if(HAVE_LIBASOUND)
       set(HAVE_ALSA TRUE)
       file(GLOB ALSA_SOURCES ${SDL2_SOURCE_DIR}/src/audio/alsa/*.c)
       set(SOURCE_FILES ${SOURCE_FILES} ${ALSA_SOURCES})
diff -r 7d5a98aac368 configure.in
--- a/configure.in	Thu Jun 25 07:17:08 2015 -0700
+++ b/configure.in	Sun Jun 28 00:55:51 2015 +0300
@@ -770,7 +770,7 @@
 AC_HELP_STRING([--enable-alsa], [support the ALSA audio API [[default=yes]]]),
                   , enable_alsa=yes)
     if test x$enable_audio = xyes -a x$enable_alsa = xyes; then
-        AM_PATH_ALSA(0.9.0, have_alsa=yes, have_alsa=no)
+        AM_PATH_ALSA(1.0.11, have_alsa=yes, have_alsa=no)
         # Restore all flags from before the ALSA detection runs
         CFLAGS="$alsa_save_CFLAGS"
         LDFLAGS="$alsa_save_LDFLAGS"
diff -r 7d5a98aac368 configure
--- a/configure	Thu Jun 25 07:17:08 2015 -0700
+++ b/configure	Sun Jun 28 00:55:51 2015 +0300
@@ -17601,7 +17601,7 @@
 { $as_echo "$as_me:${as_lineno-$LINENO}: result: $ALSA_LIBS" >&5
 $as_echo "$ALSA_LIBS" >&6; }
 
-min_alsa_version=0.9.0
+min_alsa_version=1.0.11
 { $as_echo "$as_me:${as_lineno-$LINENO}: checking for libasound headers version >= $min_alsa_version" >&5
 $as_echo_n "checking for libasound headers version >= $min_alsa_version... " >&6; }
 no_alsa=""



Patch for SDL-1.2 (current hg, SDL-1.2 branch):

diff -r 9f8a2b28f61d configure.in
--- a/configure.in	Fri Apr 17 21:41:11 2015 +0200
+++ b/configure.in	Sun Jun 28 00:55:11 2015 +0300
@@ -361,7 +361,7 @@
 AC_HELP_STRING([--enable-alsa], [support the ALSA audio API [[default=yes]]]),
                   , enable_alsa=yes)
     if test x$enable_audio = xyes -a x$enable_alsa = xyes; then
-        AM_PATH_ALSA(0.9.0, have_alsa=yes, have_alsa=no)
+        AM_PATH_ALSA(1.0.11, have_alsa=yes, have_alsa=no)
         # Restore all flags from before the ALSA detection runs
         CFLAGS="$alsa_save_CFLAGS"
         LDFLAGS="$alsa_save_LDFLAGS"