CC3000 Wifi: Enable Debug
To enable debugging, you need to 


uncomment ENABLE_CC3K_PRINTER in Adafruit_CC3000.h
If you want to pass in some debug stream other than the default Serial, you should pass a pointer to the object (which should inherit from Print, such as SD or Client) as the last argument to the constructor in your sketch:

Adafruit_CC3000(uint8_t csPin, uint8_t irqPin, uint8_t vbatPin, uint8_t spispeed = SPI_CLOCK_DIVIDER, Print* cc3kPrinter = CC3K_DEFAULT_PRINTER);

In utility/debug.h, change the value of DEBUG_MODE to 1 (or any non-zero value)


I don't know what caused your issue but you shouldn't put this in your code:

#define _CC3000_DEBUG  1


Because most of utility/debug.h is wrapped in the usual:

#ifndef _CC3000_DEBUG
.
.
.
#endif


Your #define, depending on where it's placed, could cause most of the file to be skipped by the compiler and result in compilation errors. To be on the safe side, get rid of it and simply include utility/debug.h as needed.