Check that all necessary headers are included in error.c

Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
diff --git a/scripts/generate_errors.pl b/scripts/generate_errors.pl
index 0512d59..6260731 100755
--- a/scripts/generate_errors.pl
+++ b/scripts/generate_errors.pl
@@ -48,12 +48,16 @@
 $/ = $line_separator;
 
 my @files = <$include_dir/*.h>;
+my @necessary_include_files;
 my @matches;
 foreach my $file (@files) {
     open(FILE, "$file");
     my @grep_res = grep(/^\s*#define\s+MBEDTLS_ERR_\w+\s+\-0x[0-9A-Fa-f]+/, <FILE>);
     push(@matches, @grep_res);
     close FILE;
+    my $include_name = $file;
+    $include_name =~ s!.*/!!;
+    push @necessary_include_files, $include_name if @grep_res;
 }
 
 my $ll_old_define = "";
@@ -63,10 +67,10 @@
 my $hl_code_check = "";
 
 my $headers = "";
+my %included_headers;
 
 my %error_codes_seen;
 
-
 foreach my $line (@matches)
 {
     next if ($line =~ /compat-1.2.h/);
@@ -102,6 +106,8 @@
     # Fix faulty ones
     $include_name = "net_sockets" if ($module_name eq "NET");
 
+    $included_headers{"${include_name}.h"} = $module_name;
+
     my $found_ll = grep $_ eq $module_name, @low_level_modules;
     my $found_hl = grep $_ eq $module_name, @high_level_modules;
     if (!$found_ll && !$found_hl)
@@ -194,3 +200,15 @@
 open(ERROR_FILE, ">$error_file") or die "Opening destination file '$error_file': $!";
 print ERROR_FILE $error_format;
 close(ERROR_FILE);
+
+my $errors = 0;
+for my $include_name (@necessary_include_files)
+{
+    if (not $included_headers{$include_name})
+    {
+        print STDERR "The header file \"$include_name\" defines error codes but has not been included!\n";
+        ++$errors;
+    }
+}
+
+exit !!$errors;