Modify generate errors script

Modify generate_errors.pl such that it can now handle
opening files where the file path includes a directory
names containing spaces.

Raised in issue Mbed-TLS#6879. Fix provided by
@tom-cosgrove-arm in aforementioned issue.

Signed-off-by: Thomas Daubney <thomas.daubney@arm.com>

scripts/generate_errors.pl

@@ -60,11 +60,11 @@
 my $error_format = <FORMAT_FILE>;
 close(FORMAT_FILE);
 
-my @files = <$include_dir/*.h>;
+my @files = glob qq("$include_dir/*.h");
 my @necessary_include_files;
 my @matches;
 foreach my $file (@files) {
-    open(FILE, '<:crlf', "$file");
+    open(FILE, '<:crlf', $file) or die("$0: $file: $!");
     my $content = <FILE>;
     close FILE;
     my $found = 0;