libs: Fix auto-generation of version-script for unstable libs

When there isn't a version-script for a shared library (like for
unstable libs), we create one based on the current Xen version. But
that version-script became out-of-date as soon as Xen's version
changes and make as no way to regenerate the version-script on
rebuild.

For unstable libs, we only needs the symver to be different from a
previous release of Xen. There's an option "--default-symver" which
allow to use the soname as symver and as the soname have the Xen
release version, it will be different for every release. With
--default-symver we don't need to generate a version-script.

But we also need to know if there's already an existing version script
, for that we introduce $(version-script) to be used to point to the
path of the existing script. (Guessing if a version script exist for a
stable library with for example $(wildcard) won't work as a file will
exist when building the library without this patch.)

We don't need the version-script unless we are making the shared
library so it is removed from the "all" target.

Signed-off-by: Anthony PERARD <anthony.perard@citrix.com>
Acked-by: Andrew Cooper <andrew.cooper3@citrix.com>

.gitignore

@@ -110,8 +110,6 @@ tools/config.cache
 config/Tools.mk
 config/Stubdom.mk
 config/Docs.mk
-tools/libs/ctrl/libxenctrl.map
-tools/libs/guest/libxenguest.map
 tools/libs/guest/xc_bitops.h
 tools/libs/guest/xc_core.h
 tools/libs/guest/xc_core_arm.h
@@ -121,7 +119,6 @@ tools/libs/light/_*.[ch]
 tools/libs/light/*.pyc
 tools/libs/light/_libxl.api-for-check
 tools/libs/light/*.api-ok
-tools/libs/light/libxenlight.map
 tools/libs/light/libxl-save-helper
 tools/libs/light/dsdt*
 tools/libs/light/mk_dsdt
@@ -131,13 +128,10 @@ tools/libs/light/testidl.c
 tools/libs/light/test_timedereg
 tools/libs/light/test_fdderegrace
 tools/libs/light/tmp.*
-tools/libs/stat/libxenstat.map
 tools/libs/store/list.h
 tools/libs/store/utils.h
 tools/libs/store/xs_lib.c
 tools/libs/util/libxlu_cfg_y.output
-tools/libs/util/libxenutil.map
-tools/libs/vchan/libxenvchan.map
 tools/debugger/gdb/gdb-6.2.1-linux-i386-xen/*
 tools/debugger/gdb/gdb-6.2.1/*
 tools/debugger/gdb/gdb-6.2.1.tar.bz2