Correct typos as per GH 20435

In GH 20435 many typos in our C code were corrected.  However, this pull
request was not applied to blead and developed merge conflicts.  I
extracted diffs for the individual modified files and applied them with
'git apply', excepting four files where patch conflicts were reported.
Those files were:

        handy.h
        locale.c
        regcomp.c
        toke.c

We can handle these in a subsequent commit. Also, had to run these two
programs to keep 'make test_porting' happy:

        $ ./perl -Ilib regen/uconfig_h.pl
        $ ./perl -Ilib regen/regcomp.pl regnodes.h

1 files changed, 1 insertions, 1 deletions

diff --git a/amigaos4/amigaio.c b/amigaos4/amigaio.c
index e51186c958..698165fe6b 100644
--- a/amigaos4/amigaio.c
+++ b/amigaos4/amigaio.c
@@ -249,7 +249,7 @@ PerlIO *Perl_my_popen(pTHX_ const char *cmd, const char *mode)
         }
 
         /* Our new process is running and will close it streams etc
-         * once its done. All we need to is open the pipe via stdio
+         * once it's done. All we need to is open the pipe via stdio
          */
 
         return result;