diff --git a/mingw-w64-crt/Makefile.am b/mingw-w64-crt/Makefile.am
index dca61eb..4580481 100644
--- a/mingw-w64-crt/Makefile.am
+++ b/mingw-w64-crt/Makefile.am
@@ -928,10 +928,10 @@
 # This is cleaner for watching make output, but is only in GNU Make:
 # $(DTDEF) $(top_srcdir)/$(subst .a,.def,$(subst /lib,/,$@)) --dllname $(subst .a,.dll,$(subst lib,,$(@F)))
 lib64/libcrtdll.a lib64/libmsvcrt.a lib64/libmsvcr80.a:
-	$(DTLIB) --dllname `echo $@ | $(SED) 's|lib64/lib||;s|\.a|.dll|'` -m i386:x86-64
+	$(DTLIB) --dllname `echo $@ | $(SED) 's|lib64/lib||;s|\.a|.dll|'` -m i386:x86-64 --as-flags=--64
 
 lib64/lib%.a:
-	$(DTDEF) $(top_srcdir)/lib64/$*.def -m i386:x86-64
+	$(DTDEF) $(top_srcdir)/lib64/$*.def -m i386:x86-64 --as-flags=--64
 
 
 endif
diff --git a/mingw-w64-crt/Makefile.in b/mingw-w64-crt/Makefile.in
index 8368f54..8e6a498 100644
--- a/mingw-w64-crt/Makefile.in
+++ b/mingw-w64-crt/Makefile.in
@@ -24595,10 +24595,10 @@
 # This is cleaner for watching make output, but is only in GNU Make:
 # $(DTDEF) $(top_srcdir)/$(subst .a,.def,$(subst /lib,/,$@)) --dllname $(subst .a,.dll,$(subst lib,,$(@F)))
 @LIB64_TRUE@lib64/libcrtdll.a lib64/libmsvcrt.a lib64/libmsvcr80.a:
-@LIB64_TRUE@	$(DTLIB) --dllname `echo $@ | $(SED) 's|lib64/lib||;s|\.a|.dll|'` -m i386:x86-64
+@LIB64_TRUE@	$(DTLIB) --dllname `echo $@ | $(SED) 's|lib64/lib||;s|\.a|.dll|'` -m i386:x86-64 --as-flags=--64
 
 @LIB64_TRUE@lib64/lib%.a:
-@LIB64_TRUE@	$(DTDEF) $(top_srcdir)/lib64/$*.def -m i386:x86-64
+@LIB64_TRUE@	$(DTDEF) $(top_srcdir)/lib64/$*.def -m i386:x86-64 --as-flags=--64
 
 dist-hook:
 	rm -rf `find $(top_distdir) -name ".svn"`