sdff* cells are not parseable by yosys

[antonblanchard]

Expected Behavior

sdff* liberty files should be parseable by yosys.

Actual Behavior

ERROR: Syntax error in liberty file on line 4303.

Steps to Reproduce the Problem

yosys -p "read_liberty cells/sdffsnq/gf180mcu_fd_sc_mcu7t5v0__sdffsnq_4__tt_025C_1v80.lib"

The issue is in the test_cell() stanzas, the clear and preset statements are not quoted, eg:

        preset : !SETN ;

Adding quotes fixes it, and the liberty spec suggests they are required:

        preset : "!SETN" ;

[antonblanchard]

I can submit a patch, but I wasn't sure if the liberty files are auto created from the json or not.