ccache does not handle -fstack-usage

[vapier]

gcc's -fstack-usage flag will output a .su file alongside the object. when using ccache, that file is lost :(.

in the example below, note that there is no test.su file when using ccache:

$ echo 'int main(){return 0;}' > test.c
$ /usr/bin/gcc test.c -fstack-usage -c
$ ls test.*
test.c  test.o  test.su
$ rm test.o test.su
$ ccache gcc test.c -fstack-usage -c
$ ls test.*
test.c  test.o

[jrosdahl]

Thanks, fixed in 5af36c1.