present but cannot be compiled (Was: None)

[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!

| checking if OpenSSL support is desired... yes
| checking openssl/ssl.h usability... yes
| checking openssl/ssl.h presence... yes
| checking for openssl/ssl.h... yes
| checking for DH_free in -lcrypto... yes
| checking for SSL_new in -lssl... yes
| checking if OpenSSL support can be enabled... yes
| checking if struct tm has tm_gmtoff member... yes
| checking for XScreenSaverRegister in -lXext... no
| checking for XScreenSaverRegister in -lXss... yes
| checking X11/extensions/scrnsaver.h usability... no
| checking X11/extensions/scrnsaver.h presence... yes
| configure: WARNING: X11/extensions/scrnsaver.h: present but cannot be compiled
| configure: WARNING: X11/extensions/scrnsaver.h: check for missing 
prerequisite 
| headers?
| configure: WARNING: X11/extensions/scrnsaver.h: proceeding with the 
| preprocessor's result
| configure: WARNING:     ## ------------------------------------ ##
| configure: WARNING:     ## Report this to address@hidden ##
| configure: WARNING:     ## ------------------------------------ ##
| checking for X11/extensions/scrnsaver.h... yes
| checking krootpixmap.h usability... yes
| checking krootpixmap.h presence... yes
| checking for krootpixmap.h... yes