Some portability fixes.

include/Makefile.am: use @PERL@ to call scripts/dheadgen.pl - don't rely on #! /usr/bin/perl
scripts/dheadgen.pl: use 2-arg open() for compatibility with older Perl versions
storage/innobase/srv/srv0srv.c: Don't use C++-style comments in C code

include/Makefile.am

@@ -87,7 +87,7 @@ probes_mysql_dtrace.h: $(DTRACEPROVIDER)
 endif
 
 probes_mysql_nodtrace.h: $(DTRACEPROVIDER)
-	$(top_srcdir)/scripts/dheadgen.pl -f $(DTRACEPROVIDER) > $@
+	@PERL@ $(top_srcdir)/scripts/dheadgen.pl -f $(DTRACEPROVIDER) > $@
 
 # Don't update the files from bitkeeper
 %::SCCS/s.%

scripts/dheadgen.pl

@@ -267,23 +267,23 @@ usage() if ($infile !~ /(.+)\.d$/);
 # If the system has native support for DTrace, we'll use that binary instead.
 #
 if (-x '/usr/sbin/dtrace' && !$force) {
-	open(my $dt, '-|', "/usr/sbin/dtrace -C -h -s $infile -o /dev/stdout")
+	open(DTRACE, "-| /usr/sbin/dtrace -C -h -s $infile -o /dev/stdout")
 	    or die "can't invoke dtrace(1M)";
 
-	while (<$dt>) {
+	while (<DTRACE>) {
 		emit_dtrace($_);
 	}
 
-	close($dt);
+	close(DTRACE);
 
 	exit(0);
 }
 
 emit_prologue($infile);
 
-open(my $d, '<', $infile) or die "couldn't open $infile";
-@lines = <$d>;
-close($d);
+open(D, "< $infile") or die "couldn't open $infile";
+@lines = <D>;
+close(D);
 
 while (1) {
 	my $nl = 0;

storage/innobase/srv/srv0srv.c

@@ -422,28 +422,28 @@ FILE*	srv_misc_tmpfile;
 ulint	srv_main_thread_process_no	= 0;
 ulint	srv_main_thread_id		= 0;
 
-// The following count work done by srv_master_thread.
+/* The following count work done by srv_master_thread. */
 
-// Iterations by the 'once per second' loop.
+/* Iterations by the 'once per second' loop */
 ulint   srv_main_1_second_loops         = 0;
-// Calls to sleep by the 'once per second' loop.
+/* Calls to sleep by the 'once per second' loop */
 ulint   srv_main_sleeps                 = 0;
-// Iterations by the 'once per 10 seconds' loop.
+/* Iterations by the 'once per 10 seconds' loop */
 ulint   srv_main_10_second_loops        = 0;
-// Iterations of the loop bounded by the 'background_loop' label.
+/* Iterations of the loop bounded by the 'background_loop' label */
 ulint   srv_main_background_loops       = 0;
-// Iterations of the loop bounded by the 'flush_loop' label.
+/* Iterations of the loop bounded by the 'flush_loop' label */
 ulint   srv_main_flush_loops            = 0;
-// Calls to log_buffer_flush_to_disk.
+/* Calls to log_buffer_flush_to_disk */
 ulint   srv_sync_flush                  = 0;
-// Calls to log_buffer_flush_maybe_sync.
+/* Calls to log_buffer_flush_maybe_sync */
 ulint   srv_async_flush                 = 0;
 
-// Number of microseconds threads wait because of
-// innodb_thread_concurrency
+/* Number of microseconds threads wait because of
+innodb_thread_concurrency */
 static ib_longlong srv_thread_wait_mics = 0;
 
-// Number of microseconds for spinlock delay
+/* Number of microseconds for spinlock delay */
 static ib_longlong srv_timed_spin_delay = 0;
 
 /*