Remove package name mangling for SINGLE_LANGUAGE option

SINGLE_LANGUAGE is deprecated in favor of the LANGUAGES option. When using
multiple languages, adding these to the package file name would end up
in something like "kicad-doc-de_en_it-5.0.0". As it is questionable if
the combination of specifying LANGUAGES and building a tar.gz package
is ever used just drop the special handling for the package name.

CMakeLists.txt

@@ -118,14 +118,6 @@ endif()
 set( KICAD_DOC_INSTALL_PATH share/doc/kicad
      CACHE PATH "Install path of KiCad documentation files relative to CMAKE_INSTALL_PREFIX." )
 
-# Set the language in the package name if the package only contains a single
-# language
-if( "${SINGLE_LANGUAGE}" STREQUAL "" )
-    set( PACKAGE_LANGUAGE "" )
-else()
-    set( PACKAGE_LANGUAGE "-${SINGLE_LANGUAGE}" )
-endif()
-
 # If there is more than one build format, do not bother transforming the
 # package name, otherwise if there's only one, add it to the package name
 list( LENGTH BUILD_FORMATS BUILD_FORMATS_LENGTH )
@@ -137,5 +129,5 @@ endif()
 
 # Generate both .tar.gz package target
 set( CPACK_GENERATOR "TGZ" )
-set( CPACK_PACKAGE_FILE_NAME "kicad-doc${PACKAGE_BUILD_FORMAT}${PACKAGE_LANGUAGE}-${CPACK_PACKAGE_VERSION}" )
+set( CPACK_PACKAGE_FILE_NAME "kicad-doc${PACKAGE_BUILD_FORMAT}-${CPACK_PACKAGE_VERSION}" )
 include( CPack )

README.adoc

@@ -131,9 +131,6 @@ some languages there may only be a partial documentation output.
 
 This option is deprecated, use **LANGUAGES** instead
 
-When the **SINGLE_LANGUAGE** option is set, the package name is transformed to
-include the language.
-
 ==== PDF_GENERATOR
 
 By default CMake will use dblatex building PDFs.