Summary:
Multiple strdup() calls across lib_ccx are missing NULL checks.
If allocation fails, this causes NULL pointer dereferences
or undefined behavior.

Files affected:

• ccx_encoders_helpers.c line 100 — strdup() result passed
  directly to strtok() without NULL check
• ccx_encoders_helpers.c line 129 — same pattern
• output.c line 76 — strdup() result stored without NULL check
• ccx_common_common.c line 61 — strdup() result stored without NULL check
• matroska.c line 1047 — similar to already fixed [BUG] Unchecked strdup return value in matroska.c #2159

Suggested Fix:
Add NULL check with fatal(EXIT_NOT_ENOUGH_MEMORY, ...)
after each strdup() call, consistent with existing
pattern in ocr.c line 57.