Done. Patch can be found
here.
Two new fileds were added with following default values:
Import library filename: | $(TARGET_OUTPUT_DIR)$(TARGET_OUTPUT_BASENAME) |
Definition file filename: | $(TARGET_OUTPUT_DIR)$(TARGET_OUTPUT_BASENAME) |
One macro has been added: $(TARGET_OUTPUT_FILENAME) which is filename with extension but without path. Use this in above fields to obtain "old" behaviour (from foobar.dll you will got libfoobar.dll.a).
A word of comment. Current C::B build system is working but it is messy. Several features are implemented more than once in various places, for example adding prefixes and extensions. It is a perfect candidate for refactoring.