(RHSA-2004:586) glibc security update

The GNU libc packages (known as glibc) contain the standard C libraries
used by applications.

This errata fixes several bugs in the GNU C Library.

Fixes include (in addition to enclosed Bugzilla entries):

• fixed 32-bit atomic operations on 64-bit powerpc
• fixed -m32 -I /usr/include/nptl compilation on AMD64
• NPTL <pthread.h> should now be usable in C++ code or -pedantic -std=c89 C
• rwlocks are now available also in the _POSIX_C_SOURCE=200112L namespace
• pthread_once is no longer throw(), as the callback routine might throw
• pthread_create now correctly returns EAGAIN when thread couldn’t be
  created because of lack of memory
• fixed NPTL stack freeing in case of pthread_create failure with detached
  thread
• fixed pthread_mutex_timedlock on i386 and AMD64
• Itanium gp saving fix in linuxthreads
• fixed s390/s390x unwinding tests done during cancellation if stack frames
  are small
• fixed fnmatch(3) backslash handling
• fixed out of memory behaviour of syslog(3)
• resolver ID randomization
• fixed fim (NaN, NaN)
• glob(3) fixes for dangling symlinks
• catchsegv fixed to work with both 32-bit and 64-bit binaries on x86-64,
  s390x and ppc
• fixed reinitialization of _res when using NPTL stack cache
• updated bug reporting instructions, removed glibcbug script
• fixed infinite loop in iconv with some options
• fixed inet_aton return value
• CPU friendlier busy waiting in linuxthreads on EM64T and IA-64
• avoid blocking/masking debug signal in linuxthreads
• fixed locale program output when neither LC_ALL nor LANG is set
• fixed using of unitialized memory in localedef
• fixed mntent_r escape processing
• optimized mtrace script
• linuxthread_db fixes on ppc64
• cfi instructions in x86-64 linuxthreads vfork
• some _POSIX_C_SOURCE=200112L namespace fixes

All users of glibc should upgrade to these updated packages, which resolve
these issues.