package/gcc: drop dead code related to BR2_GCC_SUPPORTS_LIBCILKRTS

The libcilkrts library was removed from gcc 8.x, and gcc 8.x is the
oldest version we allow building (to still support PowerPC SPE). So it
means the BR2_GCC_SUPPORTS_LIBCILKRTS is basically dead code because:

	default y if !BR2_TOOLCHAIN_GCC_AT_LEAST_8

Will never evaluate to 'y' in current Buildroot.

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
Signed-off-by: Julien Olivain <ju.o@free.fr>

package/gcc/Config.in.host

@@ -51,11 +51,6 @@ config BR2_GCC_VERSION_15_X
 
 endchoice
 
-# libcilkrts was introduced in gcc 4.9 and removed in gcc 8.x
-config BR2_GCC_SUPPORTS_LIBCILKRTS
-	bool
-	default y if !BR2_TOOLCHAIN_GCC_AT_LEAST_8
-
 config BR2_GCC_SUPPORTS_DLANG
 	bool
 	default y if BR2_aarch64

package/gcc/gcc-final/gcc-final.mk

@@ -85,25 +85,6 @@ else
 HOST_GCC_FINAL_GCC_LIB_DIR = $(HOST_DIR)/$(GNU_TARGET_NAME)/lib*
 endif
 
-ifeq ($(BR2_GCC_SUPPORTS_LIBCILKRTS),y)
-
-# libcilkrts does not support v8
-ifeq ($(BR2_sparc),y)
-HOST_GCC_FINAL_CONF_OPTS += --disable-libcilkrts
-endif
-
-# Pthreads are required to build libcilkrts
-ifeq ($(BR2_PTHREADS_NONE),y)
-HOST_GCC_FINAL_CONF_OPTS += --disable-libcilkrts
-endif
-
-ifeq ($(BR2_STATIC_LIBS),y)
-# disable libcilkrts as there is no static version
-HOST_GCC_FINAL_CONF_OPTS += --disable-libcilkrts
-endif
-
-endif # BR2_GCC_SUPPORTS_LIBCILKRTS
-
 # Disable shared libs like libstdc++ if we do static since it confuses linking
 ifeq ($(BR2_STATIC_LIBS),y)
 HOST_GCC_FINAL_CONF_OPTS += --disable-shared