eglibc: enable support in the Buildroot toolchain backend

Using the newly introduced 'eglibc' package, this commit enables the
option of building a toolchain using the eglibc C library in the
Buildroot toolchain backend.

In details, this commit:

 * Creates a choice to select uClibc or eglibc in the Buildroot
   toolchain backend (in toolchain/toolchain-buildroot/Config.in), and
   removes the fact that the Buildroot toolchain backend forcefully
   enables uClibc (toolchain/Config.in).

 * Creates a BUILDROOT_LIBC variables, which points to the package
   implementing the C library (i.e either 'uclibc' or 'eglibc').

 * Modifies the gcc-final and gcc-intermediate makefiles to use the
   BUILDROOT_LIBC variable instead of hardcoding the use of uclibc.

 * Ensures that TLS support is always enabled when building eglibc.

[Peter: fix commit text to refer to BUILDROOT_LIBC]
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>

3 files changed, 44 insertions, 1 deletions

diff --git a/toolchain/Config.in b/toolchain/Config.in
index 448bccc79..53d25736c 100644
--- a/toolchain/Config.in
+++ b/toolchain/Config.in
@@ -27,7 +27,6 @@ config BR2_TOOLCHAIN_BUILDROOT
 	bool "Buildroot toolchain"
 	depends on !BR2_microblaze && !BR2_aarch64
 	select BR2_TOOLCHAIN_HAS_SHADOW_PASSWORDS
-	select BR2_TOOLCHAIN_USES_UCLIBC
 
 config BR2_TOOLCHAIN_EXTERNAL
 	bool "External toolchain"
diff --git a/toolchain/toolchain-buildroot.mk b/toolchain/toolchain-buildroot.mk
index e7241bfcf..3a0580066 100644
--- a/toolchain/toolchain-buildroot.mk
+++ b/toolchain/toolchain-buildroot.mk
@@ -2,4 +2,8 @@
 # build of binutils, uClibc, kernel headers and all the intermediate
 # gcc steps.
 
+include toolchain/helpers.mk
+
+BUILDROOT_LIBC = $(call qstrip,$(BR2_TOOLCHAIN_BUILDROOT_LIBC))
+
 toolchain-buildroot: host-gcc-final
diff --git a/toolchain/toolchain-buildroot/Config.in b/toolchain/toolchain-buildroot/Config.in
index 416695b1a..396a434ac 100644
--- a/toolchain/toolchain-buildroot/Config.in
+++ b/toolchain/toolchain-buildroot/Config.in
@@ -2,7 +2,47 @@
 
 if BR2_TOOLCHAIN_BUILDROOT
 source "package/linux-headers/Config.in.host"
+
+choice
+	prompt "C library"
+
+config BR2_TOOLCHAIN_BUILDROOT_UCLIBC
+	bool "uClibc"
+	select BR2_TOOLCHAIN_USES_UCLIBC
+	help
+	  This option selects uClibc as the C library for the
+	  cross-compilation toolchain.
+
+	  http://uclibc.org
+
+config BR2_TOOLCHAIN_BUILDROOT_EGLIBC
+	bool "eglibc (experimental)"
+	depends on BR2_arm    || BR2_armeb    || BR2_aarch64 || \
+		   BR2_i386   || BR2_mips     || BR2_mipsel  || \
+		   BR2_mips64 || BR2_mips64el || BR2_powerpc || \
+		   BR2_sh     || BR2_sh64     || BR2_sparc   || \
+		   BR2_x86_64
+	select BR2_TOOLCHAIN_USES_GLIBC
+	# our eglibc.mk enables RPC support
+	select BR2_TOOLCHAIN_HAS_NATIVE_RPC
+	help
+	  This option selects eglibc as the C library for the
+	  cross-compilation toolchain.
+
+	  The eglibc support in the Buildroot toolchain backend is
+	  very recent, and therefore marked experimental.
+
+	  http://eglibc.org
+
+endchoice
+
+config BR2_TOOLCHAIN_BUILDROOT_LIBC
+	string
+	default "uclibc" if BR2_TOOLCHAIN_BUILDROOT_UCLIBC
+	default "eglibc" if BR2_TOOLCHAIN_BUILDROOT_EGLIBC
+
 source "package/uclibc/Config.in"
+
 source "package/binutils/Config.in.host"
 source "package/gcc/Config.in.host"
 endif