present but cannot be compiled (Was: autoconf bug?)

[Akim Demaille]

Please, report this to the package maintainers, as it's a configure.ac
problem.  The Autoconf 2.57 doc says:

      Previous versions of Autoconf merely checked whether the header was
   accepted by the preprocessor.  This was changed because the old test was
   inappropriate for typical uses.  Headers are typically used to compile,
   not merely to preprocess, and the old behavior sometimes accepted
   headers that clashed at compile-time.  If you need to check whether a
   header is preprocessable, you can use `AC_PREPROC_IFELSE' (*note
   Running the Preprocessor::).
   
      This scheme, which improves the robustness of the test, also requires
   that you make sure that headers that must be included before the
   HEADER-FILE be part of the INCLUDES, (*note Default Includes::).  If
   looking for `bar.h', which requires that `foo.h' be included before if
   it exists, we suggest the following scheme:
   
   
   AC_CHECK_HEADERS([foo.h])
   AC_CHECK_HEADERS([bar.h], [], [],
   [#if HAVE_FOO_H
   # include <foo.h>
   # endif
   ])

Thanks!

| I tried to compile dvr-2.7.9 with:
| gcc-3.2
| libtool-1.4.3
| autoconf-2.57
| automake-1.7.2
| 
| and got the following output after invoking 'make'( which configures the 
thing 
| as well):
| 
| ---- 8< -----
| configure: WARNING: /usr/X11R6/include/X11/extensions/dpms.h: present but 
| cannot be compiled
| configure: WARNING: /usr/X11R6/include/X11/extensions/dpms.h: check for 
| missing prerequisite headers?
| configure: WARNING: /usr/X11R6/include/X11/extensions/dpms.h: proceeding with 
| the preprocessor's result
| configure: WARNING:     ## ------------------------------------ ##
| configure: WARNING:     ## Report this to address@hidden ##
| configure: WARNING:     ## ------------------------------------ ##
| checking for /usr/X11R6/include/X11/extensions/dpms.h... yes
| checking whether system declares DPMS functions in X11/extensions/dpms.h... 
| yes
| ----- 8< -----
| 
| dpms.h looks like this:
| 
| 
| ----- START /usr/X11R6/include/X11/extensions/dpms.h -----
| 
| /* $Xorg: dpms.h,v 1.3 2000/08/18 04:05:45 coskrey Exp $ */
| /*****************************************************************
| 
| Copyright (c) 1996 Digital Equipment Corporation, Maynard, Massachusetts.
| 
| Permission is hereby granted, free of charge, to any person obtaining a copy
| of this software and associated documentation files (the "Software"), to deal
| in the Software without restriction, including without limitation the rights
| to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
| copies of the Software.
| 
| The above copyright notice and this permission notice shall be included in
| all copies or substantial portions of the Software.
| 
| THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
| IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
| FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
| DIGITAL EQUIPMENT CORPORATION BE LIABLE FOR ANY CLAIM, DAMAGES, INCLUDING, 
| BUT NOT LIMITED TO CONSEQUENTIAL OR INCIDENTAL DAMAGES, OR OTHER LIABILITY, 
| WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR 
| IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
| 
| Except as contained in this notice, the name of Digital Equipment Corporation 
| shall not be used in advertising or otherwise to promote the sale, use or 
| other
| dealings in this Software without prior written authorization from Digital 
| Equipment Corporation.
| 
| ******************************************************************/
| /* $XFree86: xc/include/extensions/dpms.h,v 3.5 2001/01/17 17:53:20 dawes Exp 
| $ */
| 
| /*
|  * HISTORY
|  */
| /*
|  * @(#)RCSfile: dpms.h,v Revision: 1.1.4.2  (DEC) Date: 1995/11/21 19:34:17
|  */
| 
| 
| #define DPMSModeOn    0
| #define DPMSModeStandby       1
| #define DPMSModeSuspend       2
| #define DPMSModeOff   3
| 
| #ifndef DPMS_SERVER
| 
| #include <X11/X.h>
| #include <X11/Xmd.h>
| 
| extern Bool DPMSQueryExtension(Display *, int *, int *);
| extern Status DPMSGetVersion(Display *, int *, int *);
| extern Bool DPMSCapable(Display *);
| extern Status DPMSSetTimeouts(Display *, CARD16, CARD16, CARD16);
| extern Bool DPMSGetTimeouts(Display *, CARD16 *, CARD16 *, CARD16 *);
| extern Status DPMSEnable(Display *);
| extern Status DPMSDisable(Display *);
| extern Status DPMSForceLevel(Display *, CARD16);
| extern Status DPMSInfo(Display *, CARD16 *, BOOL *);
| #endif
| 
| ----- END /usr/X11R6/include/X11/extensions/dpms.h -----
| 
| 
| 
| /usr/X11R6/include/X11/X.h
| and
| /usr/X11R6/include/X11/Xmd.h
| are both present.
| 
| 
| Do you need more info?
| 
| Frank
| 
| 
|