Eclipse "Missing from PATH" Error

Download MinGW:    http://www.mingw.org/category/wiki/download
In Eclipse:
  windows >> preferences >> c/c++ >> build >> environment
    Add... (or edit if there is already something called PATH there)
    Name: PATH
    Value: C:\MinGW\bin;C:\frc
      where "C:\MinGW\bin" and "C:\frc\bin" are the actual locations of the folders on your computer
    Select the radio box "Append variables to native environment"
    Press "Apply" and then "OK"
  Project >> Index >> Rebuild Index
  
If the errors are still persisting:
  In Eclipse:
    Project >> Properties >> C\C++ General >> Preprocessor Include Paths, Macros, etc. >> Providers >> check "CDT GCC Built-in Compiler Settings" and uncheck "Use global provider shared between projects"

If the PATH errors still persist after that:
  Repeat lines 3-10, adding to the value whatever is causing the error
  It's possible that the folder in your computer is missing the specified file, or it is somewhere else, so find/download the file and add it in the PATH that eclipse says is missing.