some include missing and std=c99 needed

[yoyz]

commit : f3ec15d
Need to add on my debian in file psp2shell/psp2shell_cli/source/main.c
#include <strings.h>
#include <sys/select.h>

to avoid :
warning: implicit declaration of function 'FD_ZERO' [-Wimplicit-function-declaration]
warning: implicit declaration of function 'bzero' [-Wimplicit-function-declaration]

Need to add on my debian in file psp2shell/CMakeLists.txt
add_definitions(-std=c99)

to avoid :
error: 'for' loop initial declarations are only allowed in C99 or C11 mode