bug#6820: 24.0.50; Corrupt system-configuration-options variable when using forward slashes

[Christoph]

On Windows, the following warnig appears when specifying compiler flags 
for configure.bat with forward slashes:

gcc -I. -c -gdwarf-2 -g3 -mno-cygwin -mtune=pentium4 -O2 
-DENABLE_CHECKING -DXASSERTS -fno-crossjumping 
-IC:\Progra~2\GnuWin32\include -ID:\devel\emacs\libXpm-3.5.8\include 
-ID:\devel\emacs\libXpm-3.5.8\src -Demacs=1 -DHAVE_CONFIG_H -I../nt/inc 
-DHAVE_NTGUI=1 -DUSE_CRT_DLL=1 -o oo-spd/i386/w32.o w32.c
w32.c:1955:27: warning: unknown escape sequence '\P'
w32.c:1955:27: warning: unknown escape sequence '\G'
w32.c:1955:27: warning: unknown escape sequence '\i'
w32.c:1955:27: warning: unknown escape sequence '\d'
w32.c:1955:27: warning: unknown escape sequence '\l'
w32.c:1955:27: warning: unknown escape sequence '\i'
w32.c:1955:27: warning: unknown escape sequence '\d'
w32.c:1955:27: warning: unknown escape sequence '\l'
w32.c:1955:27: warning: unknown escape sequence '\s'

The warning occurs in the following line of
`get_emacs_configuration_options' function:

strcat (options_buffer, USER_CFLAGS);

Obviously, parts of the Windows-style path are interpreted as escape
characters.

The result is a corrupt variable `system-configuration-options':
"--with-gcc (4.4) --cflags -IC:Progra~2GnuWin32include
-ID:develmacslibXpm-3.5.8include -ID:develmacslibXpm-3.5.8src"


In GNU Emacs 24.0.50.1 (i386-mingw-nt6.1.7600) of 2010-08-07 on MARVIN
Windowing system distributor `Microsoft Corp.', version 6.1.7600
configured using `configure --with-gcc (4.4) --cflags 
-IC:Progra~2GnuWin32include -ID:develmacslibXpm-3.5.8include 
-ID:develmacslibXpm-3.5.8src'

Important settings:
  value of $LC_ALL: nil
  value of $LC_COLLATE: nil
  value of $LC_CTYPE: nil
  value of $LC_MESSAGES: nil
  value of $LC_MONETARY: nil
  value of $LC_NUMERIC: nil
  value of $LC_TIME: nil
  value of $LANG: ENU
  value of $XMODIFIERS: nil
  locale-coding-system: cp1252
  default enable-multibyte-characters: t

Major mode: C/l

Minor modes in effect:
  ido-everywhere: t
  yas/global-mode: t
  yas/minor-mode: t
  global-auto-revert-mode: t
  delete-selection-mode: t
  tooltip-mode: t
  mouse-wheel-mode: t
  file-name-shadow-mode: t
  global-font-lock-mode: t
  font-lock-mode: t
  blink-cursor-mode: t
  auto-composition-mode: t
  auto-encryption-mode: t
  auto-compression-mode: t
  size-indication-mode: t
  column-number-mode: t
  line-number-mode: t
  abbrev-mode: t

Recent input:
C-x C-f M-p M-p M-p M-n M-n d : / d e v e l <return>
e m a c s <return> e m a c s <return> t r u n <return>
s r c <return> w 3 2 <return> M-g M-g 1 9 5 5 <return>
<up> <up> C-SPC C-SPC C-n C-n C-n C-n M-w <down-mouse-1>
<mouse-1> <up> <up> <up> <up> <up> <up> <up> <up> <up>
<up> <up> <up> <up> <up> <up> <up> <up> <up> <up> <up>
<up> <up> <down> <up> <left> <down> <left> <left> <left>
<left> <left> <S-down> C-c M-w <down-mouse-1> <mouse-1>
<up> <left> C-SPC C-SPC C-n M-w <down-mouse-1> <mouse-1>
<down> <down> <down> <down> <down> <down> <down> <down>
<down> <down> <down> <down> <up> <up> <up> <left> <left>
C-c RET r e p o r <tab> <return>

Recent messages:
Loading 
c:/Users/Christoph/AppData/Roaming/.emacs.d/anything-c-adaptive-history...done
Loading c:/Users/Christoph/AppData/Roaming/.emacs.d/plugins.el 
(source)...done
Loading c:/Users/Christoph/AppData/Roaming/.emacs.d/custom.el 
(source)...done
For information about GNU Emacs and the GNU system, type C-h C-a.
Loading vc-bzr...done
Mark set [2 times]
Mark activated
Mark set [2 times]
Mark activated
call-interactively: End of buffer

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None found.

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