SDL: Allow the use of posix_spawn() instead of vfork/execlp()

From 38b35a3414910df342a9aa0050002ebbc6ffcc5b Mon Sep 17 00:00:00 2001
From: Elad Lahav <[EMAIL REDACTED]>
Date: Tue, 10 Jan 2023 07:02:00 -0500
Subject: [PATCH] Allow the use of posix_spawn() instead of vfork/execlp()

---
 include/build_config/SDL_build_config.h.cmake |  2 ++
 src/misc/unix/SDL_sysurl.c                    | 15 +++++++++++++++
 2 files changed, 17 insertions(+)

diff --git a/include/build_config/SDL_build_config.h.cmake b/include/build_config/SDL_build_config.h.cmake
index bb287e7f55c5..500814d988f6 100644
--- a/include/build_config/SDL_build_config.h.cmake
+++ b/include/build_config/SDL_build_config.h.cmake
@@ -262,6 +262,8 @@
 #cmakedefine HAVE_XINPUT_GAMEPAD_EX @HAVE_XINPUT_GAMEPAD_EX@
 #cmakedefine HAVE_XINPUT_STATE_EX @HAVE_XINPUT_STATE_EX@
 
+#cmakedefine USE_POSIX_SPAWN @USE_POSIX_SPAWN@
+
 /* SDL internal assertion support */
 #if @SDL_DEFAULT_ASSERT_LEVEL_CONFIGURED@
 #cmakedefine SDL_DEFAULT_ASSERT_LEVEL @SDL_DEFAULT_ASSERT_LEVEL@
diff --git a/src/misc/unix/SDL_sysurl.c b/src/misc/unix/SDL_sysurl.c
index 510ba40432a5..b581daee8ecb 100644
--- a/src/misc/unix/SDL_sysurl.c
+++ b/src/misc/unix/SDL_sysurl.c
@@ -28,11 +28,25 @@
 #include <unistd.h>
 #include <sys/wait.h>
 #include <errno.h>
+#if USE_POSIX_SPAWN
+#include <spawn.h>
+extern char **environ;
+#endif
 
 int SDL_SYS_OpenURL(const char *url)
 {
     const pid_t pid1 = fork();
     if (pid1 == 0) { /* child process */
+#if USE_POSIX_SPAWN
+        pid_t pid2;
+        const char *args[] = { "xdg-open", url, NULL };
+        if (posix_spawnp(&pid2, args[0], NULL, NULL, (char **)args, environ) == 0) {
+            /* Child process doesn't wait for possibly-blocking grandchild. */
+            _exit(EXIT_SUCCESS);
+        } else {
+            _exit(EXIT_FAILURE);
+        }
+#else
         pid_t pid2;
         /* Clear LD_PRELOAD so Chrome opens correctly when this application is launched by Steam */
         unsetenv("LD_PRELOAD");
@@ -47,6 +61,7 @@ int SDL_SYS_OpenURL(const char *url)
             /* Child process doesn't wait for possibly-blocking grandchild. */
             _exit(EXIT_SUCCESS);
         }
+#endif
     } else if (pid1 < 0) {
         return SDL_SetError("fork() failed: %s", strerror(errno));
     } else {