diff --git a/src/diff.c b/src/diff.c
index 1d39f90..75af70d 100644
--- a/src/diff.c
+++ b/src/diff.c
@@ -161,7 +161,7 @@ const char *stripped (const char *name, int num_components)
 
 unsigned long calculate_num_lines (const char *atatline, char which)
 {
-        char *p = strchr (atatline, which);
+        const char *p = strchr (atatline, which);
         if (!p)
                 return 1;
         while (*p && *p != ',' && *p != ' ') p++;
@@ -189,7 +189,7 @@ int read_atatline (const char *atatline,
 {
 	char *endptr;
 	unsigned long res;
-	char *p;
+	const char *p;
 
 	if (orig_offset) {
 		p = strchr (atatline, '-');
diff --git a/src/patch_scanner.c b/src/patch_scanner.c
index e9971b6..5ac07e3 100644
--- a/src/patch_scanner.c
+++ b/src/patch_scanner.c
@@ -1123,7 +1123,7 @@ static int scanner_emit_hunk_header(patch_scanner_t *scanner, const char *line)
 {
     char *endptr;
     unsigned long res;
-    char *p;
+    const char *p;
     const char *context_start;
 
     /* Parse @@ -<orig_offset>[,<orig_count>] +<new_offset>[,<new_count>] @@[<context>] */
diff --git a/src/rediff.c b/src/rediff.c
index 10e6765..7a4546f 100644
--- a/src/rediff.c
+++ b/src/rediff.c
@@ -265,7 +265,7 @@ static void copy_to (struct hunk *from, struct hunk *upto,
 }
 
 /* Deal with an added hunk. */
-static long added_hunk (const char *meta, long offset, FILE *modify, FILE *t,
+static long added_hunk (char *meta, long offset, FILE *modify, FILE *t,
 			unsigned long morig_count, unsigned long mnew_count)
 {
 	long this_offset = 0;
diff --git a/src/util.c b/src/util.c
index 49d2f5f..6393017 100644
--- a/src/util.c
+++ b/src/util.c
@@ -253,7 +253,7 @@ FILE *xopen_seekable (const char *name, const char *mode)
 /* unzip if needed */
 FILE *xopen_unzip (const char *name, const char *mode)
 {
-	char *p, *zprog = NULL;
+	const char *p, *zprog = NULL;
 	FILE *fi, *fo;
 	const size_t buflen = 64 * 1024;
 	char *buffer;
@@ -602,7 +602,7 @@ char patch_determine_file_status(const struct patch_headers *headers, int empty_
 
 		/* Parse hunk headers from the patch to determine if files are empty */
 		for (unsigned int i = 0; i < headers->num_headers; i++) {
-			const char *line = headers->header_lines[i];
+			char *line = headers->header_lines[i];
 
 			/* Look for unified diff hunk headers: @@ -offset,count +offset,count @@ */
 			if (strncmp(line, "@@ ", 3) == 0) {