do not install Function.cc, as it's not a header
diff --git a/CMakeLists.txt b/CMakeLists.txt
index 7485b2a..fe5911c 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -572,7 +572,6 @@
     poppler/FontEncodingTables.h
     poppler/FontInfo.h
     poppler/Form.h
-    poppler/Function.cc
     poppler/Function.h
     poppler/Gfx.h
     poppler/GfxFont.h