Fix make install-gcc-specs with empty GCC_SPECS_FILES

	* gcc-interface/Makefile.in (install-gcc-specs): Use foreach.
	Honor DESTDIR.

From-SVN: r270947

gcc/ada/ChangeLog

+2019-05-07  Rainer Orth  <ro@CeBiTec.Uni-Bielefeld.DE>
+
+	* gcc-interface/Makefile.in (install-gcc-specs): Use foreach.
+	Honor DESTDIR.
+
 2019-04-29  Michael K. Darling  <darlingm@gmail.com>
 
 	* gnatvsn.ads: Bump Library_Version to 10.

gcc/ada/gcc-interface/Makefile.in

@@ -505,9 +505,8 @@ gnatlink-re: ../stamp-tools gnatmake-re
 install-gcc-specs:
 #	Install all the requested GCC spec files.
 
-	for f in $(GCC_SPEC_FILES); do \
-	    $(INSTALL_DATA_DATE) $(srcdir)/ada/$$f $(libsubdir)/; \
-	done
+	$(foreach f,$(GCC_SPEC_FILES), \
+	    $(INSTALL_DATA_DATE) $(srcdir)/ada/$(f) $(DESTDIR)$(libsubdir)/;)
 
 install-gnatlib: ../stamp-gnatlib-$(RTSDIR) install-gcc-specs
 	$(RMDIR) $(DESTDIR)$(ADA_RTL_OBJ_DIR)