diff --git a/doc/Makefile.in b/doc/Makefile.in
index b3348777..046d5a39 100644
--- a/doc/Makefile.in
+++ b/doc/Makefile.in
@@ -100,7 +100,9 @@ VERSION = @VERSION@
 am__include = @am__include@
 am__quote = @am__quote@
 arch = @arch@
+build_arch = @build_arch@
 install_sh = @install_sh@
+target_os = @target_os@
 
 # man pages that go into section 3:
 man3_MANS = libunwind.man libunwind-dynamic.man libunwind-ia64.man	\