merge from gcc

libiberty/pexecute.txh

@@ -0,0 +1,63 @@
+@deftypefn Extension int pexecute (const char *@var{program}, char * const *@var{argv}, const char *@var{this_pname}, const char *@var{temp_base}, char **@var{errmsg_fmt}, char **@var{errmsg_arg}, int flags)
+
+Executes a program.
+
+@var{program} and @var{argv} are the arguments to
+@code{execv}/@code{execvp}.
+
+@var{this_pname} is name of the calling program (i.e., @code{argv[0]}).
+
+@var{temp_base} is the path name, sans suffix, of a temporary file to
+use if needed.  This is currently only needed for MS-DOS ports that
+don't use @code{go32} (do any still exist?).  Ports that don't need it
+can pass @code{NULL}.
+
+(@code{@var{flags} & PEXECUTE_SEARCH}) is non-zero if @env{PATH}
+should be searched (??? It's not clear that GCC passes this flag
+correctly).  (@code{@var{flags} & PEXECUTE_FIRST}) is nonzero for the
+first process in chain.  (@code{@var{flags} & PEXECUTE_FIRST}) is
+nonzero for the last process in chain.  The first/last flags could be
+simplified to only mark the last of a chain of processes but that
+requires the caller to always mark the last one (and not give up
+early if some error occurs).  It's more robust to require the caller
+to mark both ends of the chain.
+
+The result is the pid on systems like Unix where we
+@code{fork}/@code{exec} and on systems like WIN32 and OS/2 where we
+use @code{spawn}.  It is up to the caller to wait for the child.
+
+The result is the @code{WEXITSTATUS} on systems like MS-DOS where we
+@code{spawn} and wait for the child here.
+
+Upon failure, @var{errmsg_fmt} and @var{errmsg_arg} are set to the
+text of the error message with an optional argument (if not needed,
+@var{errmsg_arg} is set to @code{NULL}), and @minus{}1 is returned.
+@code{errno} is available to the caller to use.
+
+@end deftypefn
+
+@deftypefn Extension int pwait (int @var{pid}, int *@var{status}, int @var{flags})
+
+Waits for a program started by @code{pexecute} to finish.
+
+@var{pid} is the process id of the task to wait for. @var{status} is
+the `status' argument to wait. @var{flags} is currently unused
+(allows future enhancement without breaking upward compatibility).
+Pass 0 for now.
+
+The result is the pid of the child reaped, or -1 for failure
+(@code{errno} says why).
+
+On systems that don't support waiting for a particular child,
+@var{pid} is ignored.  On systems like MS-DOS that don't really
+multitask @code{pwait} is just a mechanism to provide a consistent
+interface for the caller.
+
+@end deftypefn
+
+@undocumented pfinish
+
+pfinish: finish generation of script
+
+pfinish is necessary for systems like MPW where a script is generated
+that runs the requested programs.