toolchain: use glibc for powerpc64 builds

Neither uClibc nor musl currently have working support for powerpc64 in
big endian mode. Thus, default to using glibc for this architecture.

Signed-off-by: Florian Larysch <fl@n621.de>

toolchain/Config.in

@@ -238,6 +238,7 @@ comment "C Library"
 choice
 	prompt "C Library implementation" if TOOLCHAINOPTS
 	default LIBC_USE_UCLIBC if arc
+	default LIBC_USE_GLIBC if powerpc64
 	default LIBC_USE_MUSL
 	help
 	  Select the C library implementation.
@@ -250,13 +251,13 @@ choice
 	config LIBC_USE_UCLIBC
 		select USE_UCLIBC
 		bool "Use uClibc"
-		depends on !(aarch64 || aarch64_be)
+		depends on !(aarch64 || aarch64_be || powerpc64)
 		depends on BROKEN || !(arm || armeb || i386 || x86_64 || mips || mipsel || mips64 || mips64el || powerpc)
 
 	config LIBC_USE_MUSL
 		select USE_MUSL
 		bool "Use musl"
-		depends on !(arc)
+		depends on !(arc || powerpc64)
 
 endchoice
 
@@ -274,6 +275,7 @@ config GDB
 	  Enable if you want to build the gdb.
 
 config USE_GLIBC
+	default y if !TOOLCHAINOPTS && !EXTERNAL_TOOLCHAIN && !NATIVE_TOOLCHAIN && (powerpc64)
 	bool
 
 config USE_UCLIBC
@@ -281,7 +283,7 @@ config USE_UCLIBC
 	bool
 
 config USE_MUSL
-	default y if !TOOLCHAINOPTS && !EXTERNAL_TOOLCHAIN && !NATIVE_TOOLCHAIN && !(arc)
+	default y if !TOOLCHAINOPTS && !EXTERNAL_TOOLCHAIN && !NATIVE_TOOLCHAIN && !(arc || powerpc64)
 	bool
 
 config USE_EXTERNAL_LIBC