libc/uClibc: add patch to fix fork in threads with ARM EABI

uClibc-0.9.32 requires libgcc_eh.a (for ARM EABI), but only when libubacktrace
is enabled. As this is not the default, provide a workaround to disable linking
with libgcc_eh.a if libubacktrace is not selected.

This will however still break if uClibc is configured to enable libubacktrace,
but it requires a fix in gcc, and we can take care of that later.

Reported-by: Grant Edwards <grant.b.edwards@gmail.com>
Reported-by: Tor Krill <tor@codeknot.com>
Tested-by: Tor Krill <tor@codeknot.com>
Signed-off-by: "Yann E. MORIN" <yann.morin.1998@anciens.enib.fr>

 # ARM specific configuration file

 ## select ARCH_SUPPORTS_32

 ## select ARCH_DEFAULT_32

 ## select ARCH_SUPPORTS_BOTH_MMU

 ## select ARCH_DEFAULT_HAS_MMU

 ## select ARCH_SUPPORTS_BOTH_ENDIAN

 ## select ARCH_DEFAULT_LE

 ## select ARCH_SUPPORT_ARCH

 ## select ARCH_SUPPORT_CPU

 ## select ARCH_SUPPORT_TUNE

 ## select ARCH_SUPPORT_FPU

 ##

 ## help The ARM architecture, as defined by:

 ## help     http://www.arm.com/