tests.makeBinaryWrapper: avoid lib.fileset

pkgs/test/make-binary-wrapper/basic/basic.c

@@ -0,0 +1,7 @@
+#include <unistd.h>
+#include <stdlib.h>
+
+int main(int argc, char **argv) {
+    argv[0] = "/send/me/flags";
+    return execv("/send/me/flags", argv);
+}

pkgs/test/make-binary-wrapper/basic/basic.env

@@ -0,0 +1,2 @@
+CWD=SUBST_CWD
+SUBST_ARGV0