Revert "configure.ac: honour LLVM_LIBDIR when linking against LLVM"

This reverts commit a39ad18593.

The commit aims to address "missing" -L/foo/bar during linking stage. At
the same time it doesn't add the -L and yet the LLVM_LDFLAGS [which
provide -L/foo/bar] are already used throughout.

Seems like something pretty unique (broken?) on my end. Since the commit
introduces issues (due to the missing -L) revert until we get to the
root of it (PEBKAC or a genuine issue).

configure.ac

@@ -1985,6 +1985,8 @@ AC_SUBST([LLVM_BINDIR])
 AC_SUBST([LLVM_CFLAGS])
 AC_SUBST([LLVM_CPPFLAGS])
 AC_SUBST([LLVM_CXXFLAGS])
+AC_SUBST([LLVM_LIBDIR])
+AC_SUBST([LLVM_LIBS])
 AC_SUBST([LLVM_LDFLAGS])
 AC_SUBST([LLVM_INCLUDEDIR])
 AC_SUBST([LLVM_VERSION])
@@ -2540,9 +2542,7 @@ if test "x$MESA_LLVM" != x0; then
             LLVM_LIBS="$LLVM_LIBS `$LLVM_CONFIG --system-libs`"
         fi
     fi
-    LLVM_LIBS="$LLVM_LIBDIR $LLVM_LIBS"
 fi
-AC_SUBST([LLVM_LIBS])
 
 AM_CONDITIONAL(HAVE_GALLIUM_SVGA, test "x$HAVE_GALLIUM_SVGA" = xyes)
 AM_CONDITIONAL(HAVE_GALLIUM_I915, test "x$HAVE_GALLIUM_I915" = xyes)