common: rename getc() to getchar()

The sandbox is built with the SDL2 library with invokes the X11 library
which in turn calls getc(). But getc() in glibc is defined as

    int getc(FILE *)

This does not match our definition.

    int getc(void)

The sandbox crashes when called with parameter -l.

Rename our library symbol getc() to getchar().

Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
Reviewed-by: Tom Rini <trini@konsulko.com>
Reviewed-by: Simon Glass <sjg@chromium.org>

common/cli_readline.c

@@ -68,7 +68,7 @@ static char *delete_char (char *buffer, char *p, int *colp, int *np, int plen)
 #define CREAD_HIST_CHAR		('!')
 
 #define getcmd_putch(ch)	putc(ch)
-#define getcmd_getch()		getc()
+#define getcmd_getch()		getchar()
 #define getcmd_cbeep()		getcmd_putch('\a')
 
 #define HIST_MAX		20
@@ -571,7 +571,7 @@ int cli_readline_into_buffer(const char *const prompt, char *buffer,
 			return -2;	/* timed out */
 		WATCHDOG_RESET();	/* Trigger watchdog, if needed */
 
-		c = getc();
+		c = getchar();
 
 		/*
 		 * Special character handling