diff --git a/gzdoom.spec b/gzdoom.spec
index 0999d8e..2496aba 100644
--- a/gzdoom.spec
+++ b/gzdoom.spec
@@ -73,8 +73,9 @@ GZDoom is a port (a modification) of the original Doom source code, featuring:
 
 %prep
 %autosetup -n %name-g%version -p1
+perl -i -pe 's{__DATE__}{"does not matter when"}g' src/common/platform/posix/sdl/i_main.cpp
+perl -i -pe 's{<unknown version>}{%version}g' tools/updaterevision/UpdateRevision.cmake
 rm -Rf glslang src/common/rendering/vulkan/thirdparty/vulkan
-perl -i -pe 's{__DATE__}{""}g' src/common/platform/posix/sdl/i_main.cpp
 mkdir -p extra_include/glslang
 %if 0%{?suse_version} && 0%{?suse_version} < 1550
 touch extra_include/glslang/build_info.h