Re: [gentoo-dev] Unofficial Gentoo Development Guide and Autotools

[Mike Frysinger]

On Thursday 19 May 2005 01:53 pm, Chris White wrote:
> AC_CHECK_LIB(mng, mng_initialize,
>         [ AC_CHECK_HEADER(libmng.h,
>                 [ have_libmng=yes
>                   MNG_LIBS="-lmng" ],
>                 AC_MSG_RESULT([*** All libmng dependent parts will be
> disabled ***]))],
>         AC_MSG_RESULT([*** All libmng dependent parts will be disabled
> ***]))
> AM_CONDITIONAL(HAVE_LIBMNG, test x"$have_libmng" = "xyes")
> AC_SUBST(MNG_LIBS)
>
> The configure script will check for libmng.h and run off of that.
> You're probably going to need to patch that.. because if the script's
> lib checking functionality isn't lib64 friendly, you're gonna see a
> whole world of chaos.

this is a good example of how a package detects libmng at configure time, but 
doesnt allow you to explicitly control enabling/disabling

but to address the lib64 issue ... i dont see how this block of code has to 
care even 1 bit about the library paths on the system ... AC_CHECK_HEADER 
will simply create a small C file with '#include <libmng.h>' and then try to 
compile it ... then if it works, it will add '-lmng' to LDFLAGS ...

how does linking paths come into play at all in this example ?  here the 
script will simply let the compiler use its own judgment in locating a 
suitable candidate for '-lmng'
-mike
-- 
gentoo-dev@g.o mailing list