build system: Introduce libextension variable

This variable is the suffix to use for finding libraries when doing
compile-time linking.  For now we always set it to ".so" - so no
functional change.

In a forthcoming patch it may take on different values.

Signed-off-by: Ian Jackson <ian.jackson@eu.citrix.com>
Acked-by: Ian Campbell <ian.campbell@citrix.com>

tools/Rules.mk

@@ -23,21 +23,22 @@ XENSTORE_XENSTORED ?= y
 
 INSTALL_SHLIB = $(INSTALL_PROG)
 SYMLINK_SHLIB = ln -sf
+libextension = .so
 
 CFLAGS_libxenctrl = -I$(XEN_LIBXC) $(CFLAGS_xeninclude)
-LDLIBS_libxenctrl = $(XEN_LIBXC)/libxenctrl.so
+LDLIBS_libxenctrl = $(XEN_LIBXC)/libxenctrl$(libextension)
 SHLIB_libxenctrl  = -Wl,-rpath-link=$(XEN_LIBXC)
 
 CFLAGS_libxenguest = -I$(XEN_LIBXC) $(CFLAGS_xeninclude)
-LDLIBS_libxenguest = $(XEN_LIBXC)/libxenguest.so
+LDLIBS_libxenguest = $(XEN_LIBXC)/libxenguest$(libextension)
 SHLIB_libxenguest  = -Wl,-rpath-link=L$(XEN_LIBXC)
 
 CFLAGS_libxenstore = -I$(XEN_XENSTORE) $(CFLAGS_xeninclude)
-LDLIBS_libxenstore = $(XEN_XENSTORE)/libxenstore.so
+LDLIBS_libxenstore = $(XEN_XENSTORE)/libxenstore$(libextension)
 SHLIB_libxenstore  = -Wl,-rpath-link=$(XEN_XENSTORE)
 
 CFLAGS_libxenstat  = -I$(XEN_LIBXENSTAT)
-LDLIBS_libxenstat  = $(SHLIB_libxenctrl) $(SHLIB_libxenstore) $(XEN_LIBXENSTAT)/libxenstat.so
+LDLIBS_libxenstat  = $(SHLIB_libxenctrl) $(SHLIB_libxenstore) $(XEN_LIBXENSTAT)/libxenstat$(libextension)
 SHLIB_libxenstat  = -Wl,-rpath-link=$(XEN_LIBXENSTAT)
 
 CFLAGS_libxenvchan = -I$(XEN_LIBVCHAN)
@@ -61,7 +62,7 @@ SHLIB_libblktapctl  =
 endif
 
 CFLAGS_libxenlight = -I$(XEN_XENLIGHT) $(CFLAGS_libxenctrl) $(CFLAGS_xeninclude)
-LDLIBS_libxenlight = $(XEN_XENLIGHT)/libxenlight.so $(SHLIB_libxenctrl) $(SHLIB_libxenstore) $(SHLIB_libblktapctl)
+LDLIBS_libxenlight = $(XEN_XENLIGHT)/libxenlight$(libextension) $(SHLIB_libxenctrl) $(SHLIB_libxenstore) $(SHLIB_libblktapctl)
 SHLIB_libxenlight  = -Wl,-rpath-link=$(XEN_XENLIGHT)
 
 CFLAGS += -D__XEN_TOOLS__