20121228 bw.aljex@gmail.com - Fix writing id3 tags error

Was using tmpnam() to make a temp filename,
then rename() to move the temp file over the original file.

rename() requires both source and dest to be on the same fs, so it's
not safe to use tmpnam() to make a temp filename since that uses /tmp
and /tmp can often be a separate fs, often tmpfs.

Instead just tack a few extra chars like ".pt" (pianonbar temp)
onto the end of the normal output mp3/m4a filename for the temp file.
Ensures write permission as well as same-fs.
".pt" unlike say ".tmp" should be odd enough to allow for find & delete safely.
ex: find ./mp3 -name '*.pt' -delete

FIXME: linux-specific limits.h for PATH_MAX
FIXME: ".pt" hardcoded in two differe places, two different files

diff -ur pianobarfly/src/fly_id3.c pianobarfly_bkw/src/fly_id3.c
--- pianobarfly/src/fly_id3.c	2012-12-28 12:07:17.976172340 -0500
+++ pianobarfly_bkw/src/fly_id3.c	2012-12-28 12:32:26.539652902 -0500
@@ -34,6 +34,7 @@
 #include <stdlib.h>
 #include <string.h>
 #include <unistd.h>
+#include <linux/limits.h>
 
 #include "fly.h"
 #include "fly_id3.h"
@@ -235,8 +236,7 @@
 	FILE* audio_file = NULL;
 	FILE* tmp_file = NULL;
 	uint8_t audio_buffer[BAR_FLY_COPY_BLOCK_SIZE];
-	char tmp_file_path[L_tmpnam];
-	char* junk;
+	char tmp_file_path[PATH_MAX];
 	size_t read_count;
 	size_t write_count;
 
@@ -286,12 +286,10 @@
 
 	/*
 	 * Open the tmp file.
-	 *
-	 * Assigning the return value of tmpnam() to a junk pointer to get the
-	 * compiler to be quiet.
 	 */
-	junk = tmpnam(tmp_file_path);
-	junk = junk;
+	tmp_file_path[0] = '\0';
+	strcat (tmp_file_path, file_path);
+	strcat (tmp_file_path, ".pt");
 	tmp_file = fopen(tmp_file_path, "w+b");
 	if (tmp_file == NULL) {
 		BarUiMsg(settings, MSG_ERR, "Could not open the temporary file (%s) "
diff -ur pianobarfly/src/fly_mp4.c pianobarfly_bkw/src/fly_mp4.c
--- pianobarfly/src/fly_mp4.c	2012-12-28 12:07:17.980172359 -0500
+++ pianobarfly_bkw/src/fly_mp4.c	2012-12-28 11:50:54.603296057 -0500
@@ -57,6 +57,7 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
+#include <linux/limits.h>
 
 #include "fly.h"
 #include "fly_mp4.h"
@@ -1902,8 +1903,7 @@
 	size_t audio_buf_size;
 	size_t read_count;
 	size_t write_count;
-	char tmp_file_path[L_tmpnam];
-	char* junk;
+	char tmp_file_path[PATH_MAX];
 	size_t atom_size;
 	BarFlyMp4Atom_t* atom;
 
@@ -1912,12 +1912,10 @@
 
 	/*
 	 * Open the tmp file.
-	 *
-	 * Assigning the return value of tmpnam() to a junk pointer to get the
-	 * compiler to be quiet.
 	 */
-	junk = tmpnam(tmp_file_path);
-	junk = junk;
+	tmp_file_path[0] = '\0';
+	strcat (tmp_file_path, tag->file_path);
+	strcat (tmp_file_path, ".pt");
 	tmp_file = fopen(tmp_file_path, "wb");
 	if (tmp_file == NULL) {
 		BarUiMsg(settings, MSG_ERR,