Fix the most obvious flaws that trigger lotsa warnings.

[v-barshaw]

The compiler options -Wall -Wextra -Wshadow -Wformat=2 -Wformat-truncation=2 generate warnings.

Examples:

• declaration of 'EraseInitStruct' shadows a global declaration
• declaration of 'str' shadows a global declaration
• using integer absolute value function 'abs' when argument is of floating-point type 'double'
• implicit declaration of function 'sprintf'
• initialized field overwritten
• comparison of integer expressions of different signedness: 'int' and 'unsigned int'
• implicit declaration of function 'PID_SetMode'; did you mean 'PID_GetKd'?

Fix them.