Merge bitcoin/bitcoin#24129: build: Fix xargs warnings for Guix builds

c73415bc10 build: Fix xargs warnings for Guix builds (Hennadii Stepanov)

Pull request description:

  On master (e3ce019667) there are warnings in `./contrib/guix/guix-build` logs:
  ```
  xargs: warning: options --max-args and --replace/-I/-i are mutually exclusive, ignoring previous --max-args value
  ```

  This PR fixes such warnings.

ACKs for top commit:
  prusnak:
    utACK c73415b

Tree-SHA512: a7b55f59afbb19b78f795cea64acacf29903cfcd5fd7c37a771b073c1f2ff54555a26f3d00c1c73a8ef588396217ddf598e32b2ae961559042cc051b0aad162a

contrib/guix/libexec/build.sh

@@ -377,7 +377,7 @@ mkdir -p "$DISTSRC"
                 {
                     find "${DISTNAME}/bin" -type f -executable -print0
                     find "${DISTNAME}/lib" -type f -print0
-                } | xargs -0 -n1 -P"$JOBS" -I{} "${DISTSRC}/contrib/devtools/split-debug.sh" {} {} {}.dbg
+                } | xargs -0 -P"$JOBS" -I{} "${DISTSRC}/contrib/devtools/split-debug.sh" {} {} {}.dbg
                 ;;
         esac