Constify parameters and globals

This makes some stuff const (partially to get a more convenient
libflashrom interface).

Corresponding to flashrom svn r1639.

Signed-off-by: Nico Huber <nico.huber@secunet.com>
Signed-off-by: Stefan Tauner <stefan.tauner@alumni.tuwien.ac.at>
Acked-by: Stefan Tauner <stefan.tauner@alumni.tuwien.ac.at>
diff --git a/flashrom.c b/flashrom.c
index 6f7d680..fd438bb 100644
--- a/flashrom.c
+++ b/flashrom.c
@@ -40,13 +40,13 @@
 #include "hwaccess.h"
 
 const char flashrom_version[] = FLASHROM_VERSION;
-char *chip_to_probe = NULL;
+const char *chip_to_probe = NULL;
 int verbose_screen = MSG_INFO;
 int verbose_logfile = MSG_DEBUG2;
 
 static enum programmer programmer = PROGRAMMER_INVALID;
 
-static char *programmer_param = NULL;
+static const char *programmer_param = NULL;
 
 /*
  * Programmers supporting multiple buses can have differing size limits on
@@ -351,7 +351,7 @@
 	return 0;
 }
 
-int programmer_init(enum programmer prog, char *param)
+int programmer_init(enum programmer prog, const char *param)
 {
 	int ret;
 
@@ -517,7 +517,7 @@
  * needle and remove everything from the first occurrence of needle to the next
  * delimiter from haystack.
  */
-char *extract_param(char **haystack, const char *needle, const char *delim)
+char *extract_param(const char *const *haystack, const char *needle, const char *delim)
 {
 	char *param_pos, *opt_pos, *rest;
 	char *opt = NULL;