use relative symlinks for shared libs

The DESTDIR should not be encoded into symlinks as it is only a
temporary path.  Further, since we install the symlinks into the
same dir as the files, let's use relative links so that they can
always resolve.
Signed-off-by: NMike Frysinger <vapier@gentoo.org>

Makefile.in

@@ -176,8 +176,8 @@ install-libs: $(LIBS)
 	  chmod 755 $(DESTDIR)$(sharedlibdir)/$(SHAREDLIBV); \
 	  echo "chmod 755 $(DESTDIR)$(sharedlibdir)/$(SHAREDLIBV)"; \
 	  rm -f $(DESTDIR)$(sharedlibdir)/$(SHAREDLIB) $(DESTDIR)$(sharedlibdir)/$(SHAREDLIBM); \
-	  ln -s $(DESTDIR)$(sharedlibdir)/$(SHAREDLIBV) $(DESTDIR)$(sharedlibdir)/$(SHAREDLIB); \
-	  ln -s $(DESTDIR)$(sharedlibdir)/$(SHAREDLIBV) $(DESTDIR)$(sharedlibdir)/$(SHAREDLIBM); \
+	  ln -s $(SHAREDLIBV) $(DESTDIR)$(sharedlibdir)/$(SHAREDLIB); \
+	  ln -s $(SHAREDLIBV) $(DESTDIR)$(sharedlibdir)/$(SHAREDLIBM); \
 	  ($(LDCONFIG) || true)  >/dev/null 2>&1; \
 	fi
 	cp zlib.3 $(DESTDIR)$(man3dir)