Work around another gcc bug, where --as-needed breaks libasan. This

dies with a null pointer dereference calling crypt():

gcc -fsanitize=address -static-libasan -xc - -Wl,--as-needed -lcrypt \
  <<<$'#include<crypt.h>\nint main(void){crypt("one", "two");}' &&
  ./a.out

.github/workflows/toybox.yml

@@ -29,4 +29,4 @@ jobs:
     - name: Setup
       run: sudo apt-get install build-essential
     - name: Configure build and test
-      run: VERBOSE=all make defconfig tests
+      run: VERBOSE=all CC=clang make defconfig tests