Use portable -g flag instead of -ggdb
Use CC var instead of hardcoded gcc
Use c99 compiler
Use C99 style inline variable declarations
Use implicit return from main
Use wildcard to autodect executables to build
Fix compiler warning
Rename SRC variable to SRCS
Enable c99 via -std flag instead of CC var
Generate header dependencies
Ignore dependency file
Fix missing return statement

Amazingly this worked in C89 mode, anyone know why?
Merge branch 'c99'