Fix python 3.8

Author: virtuald

src/semiwrap/cmd_genmeson.py

@@ -90,7 +90,8 @@ def getvar(self, item: VarTypes) -> str:
 def _render_build_target(r: RenderBuffer, vc: VarCache, bt: BuildTarget):
     outvar = vc.getvar(bt)
 
-    cmd = [f"_sw_cmd_{bt.command.replace("-", "_")}"]
+    bt_cmd = bt.command.replace("-", "_")
+    cmd = [f"_sw_cmd_{bt_cmd}"]
     tinput = []
     toutput = []
     depfile = None