Declare "target_elf" for "nobuild"

Author: ivankravets

builder/main.py

@@ -208,6 +208,7 @@ def __fetch_spiffs_size(target, source, env):
 
 target_elf = env.BuildProgram()
 if "nobuild" in COMMAND_LINE_TARGETS:
+    target_elf = join("$BUILD_DIR", "${PROGNAME}.elf")
     if set(["uploadfs", "uploadfsota"]) & set(COMMAND_LINE_TARGETS):
         fetch_spiffs_size(env)
         target_firm = join("$BUILD_DIR", "spiffs.bin")