patch: use spawnve() for simple commands if available

[Keith Reynolds]

Configuration Information [Automatically generated, do not change]:
Machine: i686
OS: cygwin
Compiler: gcc
Compilation CFLAGS:  -DPROGRAM='bash.exe' -DCONF_HOSTTYPE='i686' 
-DCONF_OSTYPE='cygwin'
-DCONF_MACHTYPE='i686-pc-cygwin' -DCONF_VENDOR='pc' 
-DLOCALEDIR='/usr/local/share/locale'
-DPACKAGE='bash' -DSHELL -DHAVE_CONFIG_H -DRECYCLES_PIDS  -I. -I. -I./include 
-I./lib   -g -O2
uname output: CYGWIN_NT-5.1 keithr 1.5.18(0.132/4/2) 2005-07-02 20:30 i686 
unknown unknown Cygwin
Machine Type: i686-pc-cygwin
 
Bash Version: 3.0
Patch Level: 0
Release Status: release
 
Description:
        The attached patch uses spawnve() for simple commands (no redirection 
or fds to close).
        On cygwin, where fork() is notoriously slow, this patch cuts the 
execution time of
        bash's own configure script from 5:09 to 2:55 on my 1.7GHz P4, almost 
exactly twice as fast.
 
Repeat-By:
        Running any complicated shell script on cygwin and noting the time it 
takes to run.
 
Fix:
        Apply the attached patch.

spawnve.patch.txt
Description: Text document