Errno module is broken by preprocessor changes in GCC 5.1
Fix integer overflow issue in h2ph

https://bugs.gentoo.org/548094
https://rt.perl.org/Public/Bug/Display.html?id=123784
https://github.com/Perl/perl5/commit/816b056ffb99ae54642320e20dc30a59fd1effef
https://github.com/Perl/perl5/commit/3bea78d24634e630b610f59957e7a019205a67b2


--- a/ext/Errno/Errno_pm.PL
+++ b/ext/Errno/Errno_pm.PL
@@ -225,20 +225,31 @@ sub write_errno_pm {
     {	# BeOS (support now removed) did not enter this block
     # invoke CPP and read the output
 
+	my $inhibit_linemarkers = '';
+	if ($Config{gccversion} =~ /\A(\d+)\./ and $1 >= 5) {
+	    # GCC 5.0 interleaves expanded macros with line numbers breaking
+	    # each line into multiple lines. RT#123784
+	    $inhibit_linemarkers = ' -P';
+	}
+
 	if ($^O eq 'VMS') {
-	    my $cpp = "$Config{cppstdin} $Config{cppflags} $Config{cppminus}";
+	    my $cpp = "$Config{cppstdin} $Config{cppflags}" .
+		$inhibit_linemarkers . " $Config{cppminus}";
 	    $cpp =~ s/sys\$input//i;
 	    open(CPPO,"$cpp  errno.c |") or
 		die "Cannot exec $Config{cppstdin}";
 	} elsif ($IsMSWin32 || $^O eq 'NetWare') {
-	    open(CPPO,"$Config{cpprun} $Config{cppflags} errno.c |") or
-		die "Cannot run '$Config{cpprun} $Config{cppflags} errno.c'";
+	    my $cpp = "$Config{cpprun} $Config{cppflags}" .
+		$inhibit_linemarkers;
+	    open(CPPO,"$cpp errno.c |") or
+		die "Cannot run '$cpp errno.c'";
 	} elsif ($IsSymbian) {
-            my $cpp = "gcc -E -I$ENV{SDK}\\epoc32\\include\\libc -";
+            my $cpp = "gcc -E -I$ENV{SDK}\\epoc32\\include\\libc" .
+		$inhibit_linemarkers ." -";
 	    open(CPPO,"$cpp < errno.c |")
 		or die "Cannot exec $cpp";
         } else {
-	    my $cpp = default_cpp();
+	    my $cpp = default_cpp() . $inhibit_linemarkers;
 	    open(CPPO,"$cpp < errno.c |")
 		or die "Cannot exec $cpp";
 	}
--- a/utils/h2ph.PL
+++ b/utils/h2ph.PL
@@ -769,7 +769,7 @@ sub inc_dirs
 sub build_preamble_if_necessary
 {
     # Increment $VERSION every time this function is modified:
-    my $VERSION     = 3;
+    my $VERSION     = 4;
     my $preamble    = "$Dest_dir/_h2ph_pre.ph";
 
     # Can we skip building the preamble file?
@@ -788,6 +788,11 @@ sub build_preamble_if_necessary
 
     open  PREAMBLE, ">$preamble" or die "Cannot open $preamble:  $!";
 	print PREAMBLE "# This file was created by h2ph version $VERSION\n";
+        # Prevent non-portable hex constants from warning.
+        #
+        # We still produce an overflow warning if we can't represent
+        # a hex constant as an integer.
+        print PREAMBLE "no warnings qw(portable);\n";
 
 	foreach (sort keys %define) {
 	    if ($opt_D) {
@@ -814,6 +819,18 @@ DEFINE
 		# integer:
 		print PREAMBLE
 		    "unless (defined &$_) { sub $_() { $1 } }\n\n";
+            } elsif ($define{$_} =~ /^([+-]?0x[\da-f]+)U?L{0,2}$/i) {
+                # hex integer
+                # Special cased, since perl warns on hex integers
+                # that can't be represented in a UV.
+                #
+                # This way we get the warning at time of use, so the user
+                # only gets the warning if they happen to use this
+                # platform-specific definition.
+                my $code = $1;
+                $code = "hex('$code')" if length $code > 10;
+                print PREAMBLE
+                    "unless (defined &$_) { sub $_() { $code } }\n\n";
 	    } elsif ($define{$_} =~ /^\w+$/) {
 		my $def = $define{$_};
 		if ($isatype{$def}) {