Thanks to Mauricio Silveira for providing the patch.
SET(SYSCONFDIR "etc/sarg" CACHE PATH "The configuration directory relative to the install directory")
SET(BINDIR "bin" CACHE PATH "The directory to install the exec relative to the install directory")
-SET(MANDIR "share/man" CACHE PATH "The directory to copy the man page relative to the install directory")
+SET(MANDIR "share/man/man1" CACHE PATH "The directory to copy the man page relative to the install directory")
SET(LANGDIR "share/sarg/languages" CACHE PATH "The directory to copy the languages files relative to the install directory")
SET(FONTDIR "share/sarg/fonts" CACHE PATH "The directory to copy the fonts relative to the install directory")
SET(IMAGEDIR "share/sarg/images" CACHE PATH "The directory to copy the images files relative to the install directory")