better reporting for file i/o failier, use system error message in more places: Permission Denied, No space left, File not found etc.

- blend load/save uses os message.
- image load gives os message. (remove check for slash at end of line, just let the os report an error)
- python api load image/font/text raise errors with message (was just retuning None for image and font)
- minor edits to py api errors.

2 files changed, 2 insertions, 2 deletions

diff --git a/source/blender/blenloader/intern/readfile.c b/source/blender/blenloader/intern/readfile.c
index e670d78ff77..50a56c74cf5 100644
--- a/source/blender/blenloader/intern/readfile.c
+++ b/source/blender/blenloader/intern/readfile.c
@@ -962,7 +962,7 @@ FileData *blo_openblenderfile(char *name, ReportList *reports)
 	
 	gzfile= gzopen(name, "rb");
 
-	if (NULL == gzfile) {
+	if (gzfile == Z_NULL) {
 		BKE_report(reports, RPT_ERROR, "Unable to open");
 		return NULL;
 	} else {
diff --git a/source/blender/blenloader/intern/writefile.c b/source/blender/blenloader/intern/writefile.c
index 35fda1d8aa7..497c2d37c50 100644
--- a/source/blender/blenloader/intern/writefile.c
+++ b/source/blender/blenloader/intern/writefile.c
@@ -2481,7 +2481,7 @@ int BLO_write_file(Main *mainvar, char *dir, int write_flags, ReportList *report
 
 	file = open(tempname,O_BINARY+O_WRONLY+O_CREAT+O_TRUNC, 0666);
 	if(file == -1) {
-		BKE_report(reports, RPT_ERROR, "Unable to open file for writing.");
+		BKE_reportf(reports, RPT_ERROR, "Can't open file for writing: %s.", strerror(errno));
 		return 0;
 	}