Fix -Os getc_unlocked linknamespace, localplt issues (bug 15105, bug 19463).

Continuing the fixes for linknamespace and localplt test failures with
-Os that arise from functions not being inlined in that case, this
patch fixes such failures for getc_unlocked.

__getc_unlocked already exists; this patch makes it explicitly hidden,
calls it where needed for namespace reasons, adds an inline function
for it when inline functions are used and adds libc_hidden_proto /
libc_hidden_weak for getc_unlocked.

Tested for x86_64 (both without -Os to make sure that case continues
to work, and with -Os to make sure all the relevant linknamespace and
localplt test failures are resolved).  Because of other such failures
that remain after this patch, neither of the bugs can yet be closed.

	[BZ #15105]
	[BZ #19463]
	* libio/getc_u.c (getc_unlocked): Use libc_hidden_weak.
	* include/stdio.h [!_ISOMAC] (__getc_unlocked): Use
	attribute_hidden, and define inline if [__USE_EXTERN_INLINES].
	[!_ISOMAC] (getc_unlocked): Use libc_hidden_proto.
	* misc/getttyent.c (__getttyent): Call __getc_unlocked instead of
	getc_unlocked.
	* time/tzfile.c (__tzfile_read): Likewise.

ChangeLog

@@ -1,3 +1,15 @@
+2018-02-21  Joseph Myers  <joseph@codesourcery.com>
+
+	[BZ #15105]
+	[BZ #19463]
+	* libio/getc_u.c (getc_unlocked): Use libc_hidden_weak.
+	* include/stdio.h [!_ISOMAC] (__getc_unlocked): Use
+	attribute_hidden, and define inline if [__USE_EXTERN_INLINES].
+	[!_ISOMAC] (getc_unlocked): Use libc_hidden_proto.
+	* misc/getttyent.c (__getttyent): Call __getc_unlocked instead of
+	getc_unlocked.
+	* time/tzfile.c (__tzfile_read): Likewise.
+
 2018-02-21  Mike FABIAN  <mfabian@redhat.com>
 
 	[BZ #22517]

include/stdio.h

@@ -119,7 +119,7 @@ extern void __funlockfile (FILE *__stream) attribute_hidden;
    possible.  */
 extern int __ftrylockfile (FILE *__stream);
 
-extern int __getc_unlocked (FILE *__fp);
+extern int __getc_unlocked (FILE *__fp) attribute_hidden;
 extern wint_t __getwc_unlocked (FILE *__fp);
 
 extern int __fxprintf (FILE *__fp, const char *__fmt, ...)
@@ -187,6 +187,7 @@ libc_hidden_proto (feof_unlocked)
 extern __typeof (feof_unlocked) __feof_unlocked attribute_hidden;
 libc_hidden_proto (ferror_unlocked)
 extern __typeof (ferror_unlocked) __ferror_unlocked attribute_hidden;
+libc_hidden_proto (getc_unlocked)
 libc_hidden_proto (fmemopen)
 /* The prototype needs repeating instead of using __typeof to use
    __THROW in C++ tests.  */
@@ -219,6 +220,12 @@ __NTH (__ferror_unlocked (FILE *__stream))
 {
   return __ferror_unlocked_body (__stream);
 }
+
+__extern_inline int
+__getc_unlocked (FILE *__fp)
+{
+  return __getc_unlocked_body (__fp);
+}
 #  endif
 
 # endif /* not _ISOMAC */

libio/getc_u.c

@@ -37,4 +37,5 @@ __getc_unlocked (FILE *fp)
 }
 
 weak_alias (__getc_unlocked, getc_unlocked)
+libc_hidden_weak (getc_unlocked)
 weak_alias (__getc_unlocked, fgetc_unlocked)

misc/getttyent.c

@@ -79,7 +79,7 @@ __getttyent (void)
 		}
 		/* skip lines that are too big */
 		if (!strchr (p, '\n')) {
-			while ((c = getc_unlocked(tf)) != '\n' && c != EOF)
+			while ((c = __getc_unlocked(tf)) != '\n' && c != EOF)
 				;
 			continue;
 		}

time/tzfile.c

@@ -343,11 +343,11 @@ __tzfile_read (const char *file, size_t extra, char **extrap)
 					      sizeof (x), f) != sizeof (x),
 			    0))
 	goto lose;
-      c = getc_unlocked (f);
+      c = __getc_unlocked (f);
       if (__glibc_unlikely ((unsigned int) c > 1u))
 	goto lose;
       types[i].isdst = c;
-      c = getc_unlocked (f);
+      c = __getc_unlocked (f);
       if (__glibc_unlikely ((size_t) c > chars))
 	/* Bogus index in data file.  */
 	goto lose;
@@ -376,7 +376,7 @@ __tzfile_read (const char *file, size_t extra, char **extrap)
 
   for (i = 0; i < num_isstd; ++i)
     {
-      int c = getc_unlocked (f);
+      int c = __getc_unlocked (f);
       if (__glibc_unlikely (c == EOF))
 	goto lose;
       types[i].isstd = c != 0;
@@ -386,7 +386,7 @@ __tzfile_read (const char *file, size_t extra, char **extrap)
 
   for (i = 0; i < num_isgmt; ++i)
     {
-      int c = getc_unlocked (f);
+      int c = __getc_unlocked (f);
       if (__glibc_unlikely (c == EOF))
 	goto lose;
       types[i].isgmt = c != 0;
@@ -398,7 +398,7 @@ __tzfile_read (const char *file, size_t extra, char **extrap)
   if (sizeof (time_t) == 8 && tzspec != NULL)
     {
       /* Skip over the newline first.  */
-      if (getc_unlocked (f) != '\n'
+      if (__getc_unlocked (f) != '\n'
 	  || (__fread_unlocked (tzspec, 1, tzspec_len - 1, f)
 	      != tzspec_len - 1))
 	tzspec = NULL;
@@ -440,7 +440,7 @@ __tzfile_read (const char *file, size_t extra, char **extrap)
       char *tzstr = malloc (tzspec_len);
       if (tzstr == NULL)
 	goto lose;
-      if (getc_unlocked (f) != '\n'
+      if (__getc_unlocked (f) != '\n'
 	  || (__fread_unlocked (tzstr, 1, tzspec_len - 1, f)
 	      != tzspec_len - 1))
 	{