improve compiler test script

test/test-compilers.sh

@@ -1,7 +1,7 @@
 #!/bin/sh
 echo Testing compilers ...
 for cc in afl-cc afl-gcc afl-clang afl-clang-fast afl-clang-lto afl-gcc-fast; do
-  test -e ../$cc && { ../$cc -o t ../test-instr.c >/dev/null 2<&1 || echo Failing: $cc ; } || echo Missing: $cc
+  test -e ../$cc && { { ../$cc -o t ../test-instr.c >/dev/null 2<&1 && echo Success: $cc ; } || echo Failing: $cc ; } || echo Missing: $cc
 done
 rm -f t
 echo Done!