external/boringssl: Sync to aa2485.

This includes the following changes:

https://boringssl.googlesource.com/boringssl/+log/171b5403ee767fa0f3aecd377867db6533c3eb8f..aa24851515d6280aa1d6a8b1548fe74691df3136

Bug: 29744850
Change-Id: Id4e4a9e7a19c2f0badbaead2c39a51037ba182ed
diff --git a/src/crypto/md5/asm/md5-x86_64.pl b/src/crypto/md5/asm/md5-x86_64.pl
index 77a6e01..5ba0c62 100644
--- a/src/crypto/md5/asm/md5-x86_64.pl
+++ b/src/crypto/md5/asm/md5-x86_64.pl
@@ -110,7 +110,7 @@
 
 no warnings qw(uninitialized);
 my $flavour = shift;
-my $output  = shift || "";
+my $output  = shift;
 if ($flavour =~ /\./) { $output = $flavour; undef $flavour; }
 
 my $win64=0; $win64=1 if ($flavour =~ /[nm]asm|mingw64/ || $output =~ /\.asm$/);
@@ -120,7 +120,7 @@
 ( $xlate="${dir}../../perlasm/x86_64-xlate.pl" and -f $xlate) or
 die "can't locate x86_64-xlate.pl";
 
-open OUT,"| \"$^X\" $xlate $flavour $output";
+open OUT,"| \"$^X\" \"$xlate\" $flavour \"$output\"";
 *STDOUT=*OUT;
 
 $code .= <<EOF;