diff --git a/src/pkg/syscall/mksyscall.pl b/src/pkg/syscall/mksyscall.pl
index ecf4abdd44..9a474b6ff3 100755
--- a/src/pkg/syscall/mksyscall.pl
+++ b/src/pkg/syscall/mksyscall.pl
@@ -19,11 +19,13 @@
 # block, as otherwise the system call could cause all goroutines to
 # hang.
 
-$cmdline = "mksyscall.pl " . join(' ', @ARGV);
-$errors = 0;
-$_32bit = "";
-$nacl = 0;
-$plan9 = 0;
+use strict;
+
+my $cmdline = "mksyscall.pl " . join(' ', @ARGV);
+my $errors = 0;
+my $_32bit = "";
+my $nacl = 0;
+my $plan9 = 0;
 
 if($ARGV[0] eq "-b32") {
 	$_32bit = "big-endian";
@@ -66,7 +68,7 @@ sub parseparam($) {
 	return ($1, $2);
 }
 
-$text = "";
+my $text = "";
 while(<>) {
 	chomp;
 	s/\s+/ /g;
diff --git a/src/pkg/syscall/mksyscall_windows.pl b/src/pkg/syscall/mksyscall_windows.pl
index 83f5f03b17..c3cb142eda 100755
--- a/src/pkg/syscall/mksyscall_windows.pl
+++ b/src/pkg/syscall/mksyscall_windows.pl
@@ -23,9 +23,11 @@
 #	  //sys LoadLibrary(libname string) (handle uint32, errno int) [failretval==-1] = LoadLibraryA
 #	  and is [failretval==0] by default.
 
-$cmdline = "mksyscall_windows.pl " . join(' ', @ARGV);
-$errors = 0;
-$_32bit = "";
+use strict;
+
+my $cmdline = "mksyscall_windows.pl " . join(' ', @ARGV);
+my $errors = 0;
+my $_32bit = "";
 
 binmode STDOUT;
 
@@ -62,10 +64,10 @@ sub parseparam($) {
 	return ($1, $2);
 }
 
-$text = "";
-$vars = "";
-$mods = "";
-$modnames = "";
+my $text = "";
+my $vars = "";
+my $mods = "";
+my $modnames = "";
 while(<>) {
 	chomp;
 	s/\s+/ /g;
@@ -91,7 +93,7 @@ while(<>) {
 	if($modname eq "") {
 		$modname = "kernel32";
 	}
-	$modvname = "mod$modname";
+	my $modvname = "mod$modname";
 	if($modnames !~ /$modname/) {
 		$modnames .= ".$modname";
 		$mods .= "\t$modvname = loadDll(\"$modname.dll\")\n";
@@ -103,7 +105,7 @@ while(<>) {
 	}
 
 	# System call pointer variable name.
-	$sysvarname = "proc$sysname";
+	my $sysvarname = "proc$sysname";
 
 	# Returned value when failed
 	if($failcond eq "") {
@@ -111,17 +113,13 @@ while(<>) {
 	}
 
 	# Decide which version of api is used: ascii or unicode.
-	if($sysname !~ /W$/) {
-		$strconvfunc = "StringBytePtr";
-	} else {
-		$strconvfunc = "StringToUTF16Ptr";
-	}
+	my $strconvfunc = $sysname !~ /W$/ ? "StringBytePtr" : "StringToUTF16Ptr";
 
 	# Winapi proc address variable.
 	$vars .= sprintf "\t%s = getSysProcAddr(%s, \"%s\")\n", $sysvarname, $modvname, $sysname;
 
 	# Go function header.
-	my $out = join(', ', @out);
+	$out = join(', ', @out);
 	if($out ne "") {
 		$out = " ($out)";
 	}
@@ -242,7 +240,7 @@ while(<>) {
 				$failexpr = "$name $failcond";
 			}
 		}
-		$failexpr =~ s/(=)([0-9A-Za-z\-+])/\1 \2/;  # gofmt compatible
+		$failexpr =~ s/(=)([0-9A-Za-z\-+])/$1 $2/;  # gofmt compatible
 		if($name eq "errno") {
 			# Set errno to "last error" only if returned value indicate failure
 			$body .= "\tif $failexpr {\n";
diff --git a/src/pkg/syscall/mksysnum_darwin.pl b/src/pkg/syscall/mksysnum_darwin.pl
index 7469f2b960..fd4375b2f9 100755
--- a/src/pkg/syscall/mksysnum_darwin.pl
+++ b/src/pkg/syscall/mksysnum_darwin.pl
@@ -5,6 +5,8 @@
 #
 # Generate system call table for Darwin from sys/syscall.h
 
+use strict;
+
 my $command = "mksysnum_darwin.pl " . join(' ', @ARGV);
 
 print <<EOF;
diff --git a/src/pkg/syscall/mksysnum_freebsd.pl b/src/pkg/syscall/mksysnum_freebsd.pl
index 03f7d9e256..54872b2f48 100755
--- a/src/pkg/syscall/mksysnum_freebsd.pl
+++ b/src/pkg/syscall/mksysnum_freebsd.pl
@@ -6,6 +6,8 @@
 # Generate system call table for FreeBSD from master list
 # (for example, /usr/src/sys/kern/syscalls.master).
 
+use strict;
+
 my $command = "mksysnum_freebsd.pl " . join(' ', @ARGV);
 
 print <<EOF;
diff --git a/src/pkg/syscall/mksysnum_linux.pl b/src/pkg/syscall/mksysnum_linux.pl
index e97c87f445..ecf3641885 100755
--- a/src/pkg/syscall/mksysnum_linux.pl
+++ b/src/pkg/syscall/mksysnum_linux.pl
@@ -3,6 +3,8 @@
 # Use of this source code is governed by a BSD-style
 # license that can be found in the LICENSE file.
 
+use strict;
+
 my $command = "mksysnum_linux.pl ". join(' ', @ARGV);
 
 print <<EOF;