x86cpuid.pl: hide symbols [backport from x86_64].

crypto/perlasm/x86asm.pl

@@ -257,4 +257,6 @@ EOF
     &file($filename);
 }
 
+sub ::hidden {}
+
 1;

crypto/perlasm/x86gas.pl

@@ -251,4 +251,6 @@ ___
 sub ::dataseg
 {   push(@out,".data\n");   }
 
+*::hidden = sub { push(@out,".hidden\t$nmdecor$_[0]\n"); } if ($::elf);
+
 1;

crypto/x86cpuid.pl

@@ -455,4 +455,7 @@ my $max = "ebp";
 
 &initseg("OPENSSL_cpuid_setup");
 
+&hidden("OPENSSL_cpuid_setup");
+&hidden("OPENSSL_ia32cap_P");
+
 &asm_finish();