cmake: add cpack config

Author: MikePopoloski

CMakeLists.txt

@@ -180,3 +180,27 @@ endif()
 if(SLANG_INCLUDE_INSTALL)
   include(cmake/install-rules.cmake)
 endif()
+
+set(gitignore ${PROJECT_SOURCE_DIR}/.gitignore)
+if(SLANG_MASTER_PROJECT AND EXISTS ${gitignore})
+  # Get the list of ignored files from .gitignore.
+  file(STRINGS ${gitignore} lines)
+  list(REMOVE_ITEM lines /doc/html)
+  foreach(line ${lines})
+    string(REPLACE "/" "" line "${line}")
+    string(REPLACE "." "[.]" line "${line}")
+    string(REPLACE "*" ".*" line "${line}")
+    set(ignored_files ${ignored_files} "${line}$" "${line}/")
+  endforeach()
+  set(ignored_files ${ignored_files} /.git)
+
+  set(CPACK_PACKAGE_NAME slang)
+  set(CPACK_PACKAGE_INSTALL_DIRECTORY slang)
+  set(CPACK_PACKAGE_VENDOR "Michael Popoloski")
+  set(CPACK_SOURCE_GENERATOR ZIP)
+  set(CPACK_VERBATIM_VARIABLES YES)
+  set(CPACK_SOURCE_IGNORE_FILES ${ignored_files})
+  set(CPACK_SOURCE_PACKAGE_FILE_NAME slang-${SLANG_VERSION_STRING})
+  set(CPACK_RESOURCE_FILE_README ${PROJECT_SOURCE_DIR}/README.md)
+  include(CPack)
+endif()