toolchain/toolchain-buildroot: default to glibc as the C library

This is perhaps the most controversial change for Buildroot that can
be written in a two-liner.

Historically, we have used uClibc as our default C library, as
Buildroot was created initially as a test-bed for uClibc, and also
because uClibc made a lot of sense for embedded Linux systems, due to
its smaller size and fine-grained configurability.

Since then, the landscape of embedded Linux systems has changed. Even
though Buildroot happily supports really low-end devices, the vast
majority of Buildroot users are quite certainly running the resulting
system on a reasonably powerful platform, with significant amount of
RAM and storage. In this context, the benefits of uClibc are no longer
that much relevant, and glibc causes less "troubles". Therefore, this
patch proposes to use glibc as our default C library when using the
internal toolchain backend instead of uClibc.

Of course, we will keep the support for uClibc, which remains an
important C library choice, for space-constrained systems, or simply
for architectures that are not supported by glibc.

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
Acked-by: Arnout Vandecappelle (Essensium/Mind) <arnout@mind.be>
Acked-by: Yann E. MORIN <yann.morin.1998@free.fr>
Acked-by: Peter Korsgaard <peter@korsgaard.com>
Signed-off-by: Yann E. MORIN <yann.morin.1998@free.fr>

toolchain/toolchain-buildroot/Config.in

@@ -22,8 +22,7 @@ config BR2_TOOLCHAIN_BUILDROOT_VENDOR
 
 choice
 	prompt "C library"
-	default BR2_TOOLCHAIN_BUILDROOT_UCLIBC
-	default BR2_TOOLCHAIN_BUILDROOT_GLIBC if BR2_powerpc64
+	default BR2_TOOLCHAIN_BUILDROOT_GLIBC
 
 config BR2_TOOLCHAIN_BUILDROOT_UCLIBC
 	bool "uClibc-ng"