Avoid creating ccache directory when CCACHE_DISABLE is set
Copy dia file even if compiling failed
Support -@file.opt

Some compilers (e.g. diab) use -@ notation for options file
Spelling fixes
Merge branch 'maint'

* maint:
  Spelling fixes
  Avoid creating ccache directory when CCACHE_DISABLE is set

Conflicts:
	ccache.c