diff --git a/pkgs/tools/graphics/transfig/default.nix b/pkgs/tools/graphics/transfig/default.nix
index 960e7fd3ba3..9226809c5c5 100644
--- a/pkgs/tools/graphics/transfig/default.nix
+++ b/pkgs/tools/graphics/transfig/default.nix
@@ -11,11 +11,11 @@ stdenv.mkDerivation {
   buildInputs = [ zlib libjpeg libpng ];
 
   patches = [
-    ./patch-fig2dev-dev-Imakefile
-    ./patch-fig2dev-Imakefile
-    ./patch-transfig-Imakefile
-    ./patch-fig2dev-fig2dev.h
-    ./patch-fig2dev-dev-gensvg.c
+    ./patch-fig2dev-dev-Imakefile.patch
+    ./patch-fig2dev-Imakefile.patch
+    ./patch-transfig-Imakefile.patch
+    ./patch-fig2dev-fig2dev.h.patch
+    ./patch-fig2dev-dev-gensvg.c.patch
   ];
 
   patchPhase = ''
diff --git a/pkgs/tools/graphics/transfig/patch-fig2dev-Imakefile b/pkgs/tools/graphics/transfig/patch-fig2dev-Imakefile.patch
similarity index 100%
rename from pkgs/tools/graphics/transfig/patch-fig2dev-Imakefile
rename to pkgs/tools/graphics/transfig/patch-fig2dev-Imakefile.patch
diff --git a/pkgs/tools/graphics/transfig/patch-fig2dev-dev-Imakefile b/pkgs/tools/graphics/transfig/patch-fig2dev-dev-Imakefile.patch
similarity index 100%
rename from pkgs/tools/graphics/transfig/patch-fig2dev-dev-Imakefile
rename to pkgs/tools/graphics/transfig/patch-fig2dev-dev-Imakefile.patch
diff --git a/pkgs/tools/graphics/transfig/patch-fig2dev-dev-gensvg.c b/pkgs/tools/graphics/transfig/patch-fig2dev-dev-gensvg.c.patch
similarity index 100%
rename from pkgs/tools/graphics/transfig/patch-fig2dev-dev-gensvg.c
rename to pkgs/tools/graphics/transfig/patch-fig2dev-dev-gensvg.c.patch
diff --git a/pkgs/tools/graphics/transfig/patch-fig2dev-fig2dev.h b/pkgs/tools/graphics/transfig/patch-fig2dev-fig2dev.h.patch
similarity index 100%
rename from pkgs/tools/graphics/transfig/patch-fig2dev-fig2dev.h
rename to pkgs/tools/graphics/transfig/patch-fig2dev-fig2dev.h.patch
diff --git a/pkgs/tools/graphics/transfig/patch-transfig-Imakefile b/pkgs/tools/graphics/transfig/patch-transfig-Imakefile.patch
similarity index 100%
rename from pkgs/tools/graphics/transfig/patch-transfig-Imakefile
rename to pkgs/tools/graphics/transfig/patch-transfig-Imakefile.patch