Re: "WARNING: dlfcn.h: accepted by the compiler, rejected by the preprocessor!"

[Akim Demaille]

Thanks for the report, but please, always answer on public lists.

The problem seems to be that (according to the config.log you sent
me):

| configure:4699: checking dlfcn.h presence
| configure:4710:   -D_XOPEN_SOURCE_EXTENDED conftest.cc
| ./configure: -D_XOPEN_SOURCE_EXTENDED: command not found
| configure:4716: $? = 127
| configure: failed program was:
| | #line 4701 "configure"
| | /* confdefs.h.  */
| | 
| | #define PACKAGE_NAME ""
| | #define PACKAGE_TARNAME ""
| | #define PACKAGE_VERSION ""
| | #define PACKAGE_STRING ""
| | #define PACKAGE_BUGREPORT ""
| | #define PACKAGE "@PACKAGENAME@"
| | #define VERSION "@address@hidden@MINOR@"
| | #ifdef __cplusplus
| | #include <stdlib.h>
| | #endif
| | #define HAVE_SYS_TYPES_H 1
| | #define HAVE_SYS_STAT_H 1
| | #define HAVE_STDLIB_H 1
| | #define HAVE_STRING_H 1
| | #define HAVE_MEMORY_H 1
| | #define HAVE_STRINGS_H 1
| | #define HAVE_INTTYPES_H 1
| | #define HAVE_UNISTD_H 1
| | /* end confdefs.h.  */
| | #include <dlfcn.h>
| configure:4735: result: no
| configure:4741: WARNING: dlfcn.h: accepted by the compiler, rejected by the 
preprocessor!
| configure:4743: WARNING: dlfcn.h: proceeding with the preprocessor's result
| configure:4771: checking for dlfcn.h
| configure:4778: result: no
| configure:4796: checking how to run the C++ preprocessor
| configure:4828: g++ -E  -D_XOPEN_SOURCE_EXTENDED conftest.cc
| configure:4834: $? = 0
| configure:4866: g++ -E  -D_XOPEN_SOURCE_EXTENDED conftest.cc
| configure:4878:28: ac_nonexistent.h: No such file or directory
| configure:4872: $? = 1

i.e., for some reason ./configure first looks for the header, and then
for the preproc.  I can't find any occurrence of dlfcn.h in the
configure.ac you sent (attached here for the records)

configure.ac
Description: Text Data

Could you try to scale down this configure.ac, make it independent of
Libtool and Automake, self contained, so that it still exhibit the
problem?  Thanks a lot!