Re: [Freeciv-Dev] Silliness in FC_CHECK_X_LIB

[David Pfitzner <dwp@xxxxxxxxxxxxxx>]

Greg Wooledge wrote:
> Sverker Wiberg (sverkerw@xxxxxxxxxxxx) wrote:
> 
> > This means that listing the resolver in LIBS will link the X libraries
> > *after* and *without* the resolver, causing spurious link failures. 

> > In short, I believe that LIBS should be appended to
> > linker lines instead of prepended (LDFLAGS is prepended, btw).

>  It looks like this (on Debian
> GNU/Linux):
> 
>   After AC PATH XTRA: LIBS=, X_LIBS= -L/usr/X11R6/lib, X_PRE_LIBS= -lSM 
> -lICE, X_EXTRA_LIBS=
> 
> See, they've put -L/dir into X_LIBS, which normally goes *after*
> X_PRE_LIBS, which contains the libraries that -L/dir points to.

Is there any reason at all that the freeciv configure puts X_PRE_LIBS
_after_ X_LIBS, given that according to the autoconf docs, (talking
about AC_PATH_XTRA)

% And it checks for
% special X11R6 libraries that need to be linked with before
% `-lX11', and adds any found to the output variable `X_PRE_LIBS'.

I propose the attached patch, which puts X_PRE_LIBS in their place,
and also puts LIBS last, as Sverker wanted.   This also fixes the
problem Greg pointed out previously of including the X_PRE_LIBS
twice on the line to link the client.

I have though found another similar problem.  On Solaris, -lsocket 
and -lnsl are put in X_EXTRA_LIBS (by AC_PATH_XTRA), and then we check 
them again and put them in LIBS, so they get doubled up on the link line.

-- David

diff -u -r --exclude-from exclude_auto fc-adv/acinclude.m4 
freeciv-mod/acinclude.m4
--- fc-adv/acinclude.m4 Sat Nov 21 17:56:52 1998
+++ freeciv-mod/acinclude.m4    Sat Nov 21 18:29:57 1998
@@ -4,22 +4,21 @@
 dnl
 dnl This macro is intended to search for X11-related libraries.  It takes the
 dnl following variables for input:
-dnl   LIBS             -- prefixed to all linker lines
-dnl   X_LIBS           -- prefixed to all linker lines (after LIBS)
-dnl   X_EXTRA_LIBS     -- suffixed to all linker lines
-dnl Thus, the trial linker line will be "$LIBS $X_LIBS -l$1 $X_EXTRA_LIBS".
+dnl     X_PRE_LIBS, X_LIBS, X_EXTRA_LIBS, LIBS
+dnl These will apear on linker lines in the above order; 
+dnl thus the trial linker line will be:
+dnl     "$X_PRE_LIBS $X_LIBS -l$1 $X_EXTRA_LIBS $LIBS".
 dnl
 dnl The following variables are output:
 dnl   X_EXTRA_LIBS     -- contains "-l$1 $X_EXTRA_LIBS" if the link succeeds
 dnl
 dnl Thus, the intended usage of this macro is something like this:
 dnl   AC_PATH_XTRA
-dnl   X_LIBS="$X_LIBS $X_PRE_LIBS"
-dnl    dnl Is it just me or is AC_PATH_XTRA broken?
+dnl   dnl Is it just me or is AC_PATH_XTRA broken?
 dnl   FC_CHECK_X_LIB(X11, XOpenDisplay, , AC_MSG_ERROR("Need X11"))
 dnl   FC_CHECK_X_LIB(Xext, XShapeCombineMask)
 dnl     [etc.]
-dnl   LIBS="$LIBS $X_LIBS $X_EXTRA_LIBS"
+dnl   LIBS="$X_PRE_LIBS $X_LIBS $X_EXTRA_LIBS $LIBS"
 dnl
 AC_DEFUN(FC_CHECK_X_LIB,
 [AC_MSG_CHECKING([for $2 in X library -l$1])
@@ -30,7 +29,7 @@
 ac_lib_var=`echo $1['_']$2 | sed 'y%./+-%__p_%'`
 AC_CACHE_VAL(ac_cv_lib_$ac_lib_var,
 [ac_save_LIBS="$LIBS"
-LIBS="$LIBS $X_LIBS -l$1 $X_EXTRA_LIBS"
+LIBS="$X_PRE_LIBS $X_LIBS -l$1 $X_EXTRA_LIBS $LIBS"
 AC_TRY_LINK(dnl
 ifelse([$2], [main], , dnl Avoid conflicting decl of main.
 [/* Override any gcc2 internal prototype to avoid an error.  */
diff -u -r --exclude-from exclude_auto fc-adv/configure.in 
freeciv-mod/configure.in
--- fc-adv/configure.in Sat Nov 21 18:27:03 1998
+++ freeciv-mod/configure.in    Sat Nov 21 18:30:38 1998
@@ -86,8 +86,6 @@
 if test x$client = xtrue; then
     dnl Checks for X:
     AC_PATH_XTRA
-    dnl CFLAGS="$CFLAGS $X_CFLAGS"
-    X_LIBS="$X_LIBS $X_PRE_LIBS"
 
     dnl Checks for X libs:
     FC_CHECK_X_LIB(X11, XOpenDisplay, , AC_MSG_ERROR("Need X11"))
@@ -100,7 +98,6 @@
     else
        FC_CHECK_X_LIB(Xaw3d, main)
     fi
-    dnl LIBS="$LIBS $X_LIBS $X_EXTRA_LIBS"
 fi
 
 dnl Checks for non-X libraries: