[PATCH 0/1] MR3734: tools: Use posix_spawn() instead of fork()/execvp().

[Brendan Shanks (＠bshanks)]

`posix_spawn()` should be more efficient on all systems, especially macOS. Running `make -j12 install` in an x86_64 emulated shell on a 12-core M2 Pro system, I saw a substantial time improvement (9 minutes vs 13) and much lower system overhead.

[PATCH 1/1] tools: Use posix_spawn() instead of fork()/execvp().

[Brendan Shanks]

From: Brendan Shanks

---
 tools/tools.h | 12 +++++-------
 1 file changed, 5 insertions(+), 7 deletions(-)

diff --git a/tools/tools.h b/tools/tools.h
index fa459994eb3..7f99205aca8 100644
--- a/tools/tools.h
+++ b/tools/tools.h
@@ -57,6 +57,8 @@
 #  define strcasecmp _stricmp
 # endif
 #else
+extern char **environ;
+# include <spawn.h>
 # include <sys/wait.h>
 # include <unistd.h>
 # ifndef O_BINARY
@@ -283,13 +285,9 @@ static inline int strarray_spawn( struct strarray args )
     pid_t pid, wret;
     int status;

-    if (!(pid = fork()))
-    {
-        strarray_add( &args, NULL );
-        execvp( args.str[0], (char **)args.str );
-        _exit(1);
-    }
-    if (pid == -1) return -1;
+    strarray_add( &args, NULL );
+    if (posix_spawnp( &pid, args.str[0], NULL, NULL, (char **)args.str, environ ))
+        return -1;

while (pid != (wret = waitpid( pid, &status, 0 )))
         if (wret == -1 && errno != EINTR) break;