From fe18ede121e5782676ccec4f29b29e1a1fc7b48f Mon Sep 17 00:00:00 2001
From: Sam Lantinga <slouken@libsdl.org>
Date: Fri, 6 Nov 2009 03:37:57 +0000
Subject: [PATCH] Fixed bug #877

 Mike Frysinger      2009-11-05 09:11:43 PST

the current code assumes "unix" means fork() exists.  this doesnt work for
no-mmu linux systems as fork() cant be implemented.

simple enough to add fork/vfork tests to configure and let the rest of the code
key off of CMD_MUSIC like normal -- no more needing to hardcode unix/mac-os-x
defines in the source.
---
 configure.in | 20 ++++++++++++++++----
 music.c      |  5 -----
 music_cmd.c  |  8 ++++++--
 music_cmd.h  |  4 ++--
 4 files changed, 24 insertions(+), 13 deletions(-)

diff --git a/configure.in b/configure.in
index fad60238..7a91c3e9 100644
--- a/configure.in
+++ b/configure.in
@@ -180,10 +180,22 @@ dnl Check command-line options
 
 AC_ARG_ENABLE([music-cmd],
 AC_HELP_STRING([--enable-music-cmd], [support an external music player [[default=yes]]]),
-              [], [enable_music_cmd=yes])
-if test x$enable_music_cmd = xyes; then
-    SOURCES="$SOURCES $srcdir/music_cmd.c"
-    EXTRA_CFLAGS="$EXTRA_CFLAGS -DCMD_MUSIC"
+              [], [enable_music_cmd=detect])
+if test "x$enable_music_cmd" != xno; then
+    AC_CHECK_FUNCS([fork vfork])
+    if test "x$ac_cv_func_fork" = "xyes"; then
+        EXTRA_CFLAGS="$EXTRA_CFLAGS -DHAVE_FORK"
+    elif test "x$ac_cv_func_vfork" = "xyes"; then
+        EXTRA_CFLAGS="$EXTRA_CFLAGS -DHAVE_VFORK"
+    elif test "x$enable_music_cmd" = "xyes"; then
+        AC_MSG_ERROR([external music player not available on your platform])
+    else
+        enable_music_cmd=no
+    fi
+    if test "x$enable_music_cmd" != xno; then
+        SOURCES="$SOURCES $srcdir/music_cmd.c"
+        EXTRA_CFLAGS="$EXTRA_CFLAGS -DCMD_MUSIC"
+    fi
 fi
 
 AC_ARG_ENABLE([music-wave],
diff --git a/music.c b/music.c
index dbd5737e..03d55817 100644
--- a/music.c
+++ b/music.c
@@ -32,11 +32,6 @@
 
 #include "SDL_mixer.h"
 
-/* The music command hack is UNIX specific */
-#ifndef unix
-#undef CMD_MUSIC
-#endif
-
 #ifdef CMD_MUSIC
 #include "music_cmd.h"
 #endif
diff --git a/music_cmd.c b/music_cmd.c
index c3e694b7..5a43ddcd 100644
--- a/music_cmd.c
+++ b/music_cmd.c
@@ -23,7 +23,7 @@
 
 /* This file supports an external command for playing music */
 
-#if defined(unix) || defined(__MACOSX__) /* This is a UNIX-specific hack */
+#ifdef CMD_MUSIC
 
 #include <sys/types.h>
 #include <sys/wait.h>
@@ -143,7 +143,11 @@ static char **parse_args(char *command, char *last_arg)
 /* Start playback of a given music stream */
 void MusicCMD_Start(MusicCMD *music)
 {
+#ifdef HAVE_FORK
 	music->pid = fork();
+#else
+	music->pid = vfork();
+#endif
 	switch(music->pid) {
 	    /* Failed fork() system call */
 	    case -1:
@@ -235,4 +239,4 @@ int MusicCMD_Active(MusicCMD *music)
 	return(active);
 }
 
-#endif /* unix */
+#endif /* CMD_MUSIC */
diff --git a/music_cmd.h b/music_cmd.h
index 2a1b8da4..41757a86 100644
--- a/music_cmd.h
+++ b/music_cmd.h
@@ -22,7 +22,7 @@
 
 /* This file supports an external command for playing music */
 
-#if defined(unix) || defined(__MACOSX__) /* This is a UNIX-specific hack */
+#ifdef CMD_MUSIC
 
 #include <sys/types.h>
 #include <limits.h>
@@ -60,4 +60,4 @@ extern void MusicCMD_FreeSong(MusicCMD *music);
 /* Return non-zero if a stream is currently playing */
 extern int MusicCMD_Active(MusicCMD *music);
 
-#endif /* unix */
+#endif /* CMD_MUSIC */