ax_auto_include_headers

Given a space-separated list of INCLUDE-FILEs, AX_AUTO_INCLUDE_HEADERS will output a conditional #include for each INCLUDE-FILE. The following example demonstrates how AX_AUTO_INCLUDE_HEADERS's might be used in a configure.ac script:

     AH_BOTTOM([
       AX_AUTO_INCLUDE_HEADERS([sys/resource.h invent.h sys/sysinfo.h])dnl
     ])

The preceding invocation instructs autoheader to put the following code at the bottom of the config.h file:

     #ifdef HAVE_SYS_RESOURCE_H
     # include <sys/resource.h>
     #endif
     #ifdef HAVE_INVENT_H
     # include <invent.h>
     #endif
     #ifdef HAVE_SYS_SYSINFO_H
     # include <sys/sysinfo.h>
     #endif

Note that AX_AUTO_INCLUDE_HEADERS merely outputs #ifdef/#include/#endif blocks. The configure.ac script still needs to invoke AC_CHECK_HEADERS to #define the various HAVE_*_H preprocessor macros.

Here's an easy way to get from config.h a complete list of header files who existence is tested by the configure script:

    cat config.h | perl -ane '/ HAVE_\S+_H / && do {$_=$F[$#F-1]; s/^HAVE_//; s/_H/.h/; s|_|/|g; tr/A-Z/a-z/; print "$_ "}'

You can then manually edit the resulting list and incorporate it into one or more calls to AX_AUTO_INCLUDE_HEADERS.

AC_DEFUN([AX_AUTO_INCLUDE_HEADERS], [dnl
AC_FOREACH([AX_Header], [$1], [dnl
m4_pushdef([AX_IfDef], AS_TR_CPP(HAVE_[]AX_Header))dnl
[#]ifdef AX_IfDef
[#] include <AX_Header>
[#]endif
m4_popdef([AX_IfDef])dnl
])])