Make eltt2 c99 compliant

Some implicit headerfiles were missing, if used without -std=gnu99.
Since we do not rely on gnu99 behavior by including the header files,
we can use -std=c99, which we state explicitly in the Makefile now.

Signed-off-by: Peter Huewe <peterhuewe@gmx.de>

Makefile

@@ -2,7 +2,7 @@
 # Copyright (c) Infineon Technologies AG
 
 CC=gcc
-CFLAGS=-Wall -Wextra -g
+CFLAGS=-Wall -Wextra -std=c99 -g
 
 all: eltt2
 

eltt2.h

@@ -67,8 +67,10 @@
 #include <fcntl.h>
 #include <errno.h>
 #include <unistd.h>
+#include <getopt.h>
 #include <ctype.h>
 #include <string.h>
+#include <strings.h>
 
 //-------------"Defines"-------------
 #define TPM_RESP_MAX_SIZE		4096			///< This is the maximum possible TPM response size in bytes.