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

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:devel^[macslibXpm-3.5.8include -ID:devel^[macslibXpm-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:devel^[macslibXpm-3.5.8include 
-ID:devel^[macslibXpm-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

Load-path shadows:
None found.

Features:
(shadow sort gnus-cite mail-extr gnus-msg gnus-art mm-uu mml2015 pgg
pgg-parse pgg-def epg-config mm-view smime password-cache dig mailcap
gnus-sum nnoo gnus-group time-date gnus-undo nnmail mail-source
format-spec gnus-start gnus-spec gnus-int gnus-range gnus-win message
rfc822 mml mml-sec mm-decode mm-bodies mm-encode mail-parse rfc2231
rfc2047 rfc2045 ietf-drums mailabbrev gmm-utils mailheader gnus gnus-ems
nnheader gnus-util mail-utils mm-util mail-prsvr emacsbug vc-bzr sha1
hex-util server js2-mode-autoloads rainbow-mode-autoloads package
re-builder ibuffer nav nav-tags python-21 python nav-bufs xcscope
anything-config warnings browse-url semantic/util-modes semantic/util
semantic semantic/tag semantic/lex semantic/fw loaddefs eieio byte-opt
bytecomp byte-compile mode-local cedet imenu bookmark pp dired rx ffap
thingatpt anything google-c-style cc-mode cc-fonts cc-menus cc-cmds
cc-styles cc-align cc-engine cc-vars cc-defs grep-o-matic grep compile
comint browse-kill-ring+ browse-kill-ring second-sel ido yasnippet
dropdown-list derived easy-mmode assoc etags-table etags ring remember
zenburn color-theme edmacro kmacro wid-edit cl cl-19 sendmail regexp-opt
reporter easymenu uniquify advice help-fns advice-preload autorevert
delsel tooltip ediff-hook vc-hooks lisp-float-type mwheel dos-w32
disp-table ls-lisp w32-win w32-vars tool-bar dnd fontset image fringe
lisp-mode register page menu-bar rfn-eshadow timer select scroll-bar
mldrag mouse jit-lock font-lock syntax facemenu font-core frame cham
georgian utf-8-lang misc-lang vietnamese tibetan thai tai-viet lao
korean japanese hebrew greek romanian slovak czech european ethiopic
indian cyrillic chinese case-table epa-hook jka-cmpr-hook help simple
abbrev button minibuffer faces cus-face files text-properties overlay
md5 base64 format env code-pages mule custom widget
hashtable-print-readable backquote make-network-process multi-tty emacs)

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

[Juanma Barranquero]

> On Windows, the following warning 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

You mean backslashes. :-)

Currently we don't support passing backslashes or quotes in arguments
to the --cflags configure.bat option, because as you point out they
break compilation of w32.c:get_emacs_configuration_options.

There's no easy way to fix that from configure.bat in a simple and
portable way; the next best fix is just err out with a clear message
when running configure.bat so the user can react immediately, instead
of getting a not-so-clear error or warning during compilation.

I've implemented the check only for GCC because I don't have access to
MSVC; but it should be trivial to add if MSVC has some command option
similar to GCC's -Werror (turn any warning into an error).

    Juanma