rework mechanism for posix_spawnp calling posix_spawn

previously, a common __posix_spawnx backend was used that accepted an
additional argument for the execve variant to call in the child. this
moderately bloated up the posix_spawn function, shuffling arguments
between stack and/or registers to call a 7-argument function from a
6-argument one.

instead, tuck the exec function pointer in an unused part of the
(large) pthread_spawnattr_t structure, and have posix_spawnp duplicate
the attributes and fill in a pointer to __execvpe. the net code size
change is minimal, but the weight is shifted to the "heavier" function
which already pulls in more dependencies.

as a bonus, we get rid of an external symbol (__posix_spawnx) that had
no really good place for a declaration because it shouldn't have
existed to begin with.

1 files changed, 4 insertions, 6 deletions

diff --git a/src/process/posix_spawnp.c b/src/process/posix_spawnp.c
index 37360001..165be746 100644
--- a/src/process/posix_spawnp.c
+++ b/src/process/posix_spawnp.c
@@ -3,15 +3,13 @@
 
 int __execvpe(const char *, char *const *, char *const *);
 
-int __posix_spawnx(pid_t *restrict, const char *restrict,
-	int (*)(const char *, char *const *, char *const *),
-	const posix_spawn_file_actions_t *,
-	const posix_spawnattr_t *restrict, char *const *restrict, char *const *restrict);
-
 int posix_spawnp(pid_t *restrict res, const char *restrict file,
 	const posix_spawn_file_actions_t *fa,
 	const posix_spawnattr_t *restrict attr,
 	char *const argv[restrict], char *const envp[restrict])
 {
-	return __posix_spawnx(res, file, __execvpe, fa, attr, argv, envp);
+	posix_spawnattr_t spawnp_attr = { 0 };
+	if (attr) spawnp_attr = *attr;
+	spawnp_attr.__fn = (void *)__execvpe;	
+	return posix_spawn(res, file, fa, &spawnp_attr, argv, envp);
 }