gag Studio warnings that only occur with an adjunct proto
Studio has no equivalent to -isystem, and no option to its -errhdr that
seems equivalent.  As such, we have to gag the warnings that are induced
from the 3rd party headers when those headers are found via the adjunct,
as they will not match Studio's seemingly hard-coded exception on
`/usr/include`

*** 28,37 ****
--- 28,41 ----
  
  CPPFLAGS =      $(POLICYKIT_DBUS_CPPFLAGS) $(POLICYKIT_GLIB_CPPFLAGS) $(CPPFLAGS.master)
  
  CERRWARN +=     -_gcc=-Wno-unused-variable
  
+ # This is, unfortunately, from the glib headers.  Studio provides no
+ # equivalent to -isystem
+ CERRWARN +=     -_cc=-erroff=E_INTEGER_OVERFLOW_DETECTED
+ 
  C99MODE =       $(C99_ENABLE)
  
  ROOTLIBPCDIR =  $(ROOT)/usr/lib/pkgconfig
  ROOTLIBPC =     $(LIBPCSRC:%=$(ROOTLIBPCDIR)/%)