RISC-V: Add RV64GC Bitmanip multi-lib

This commit introduces a new multi-lib build for RV64GC with Bitmanip
extensions enabled: rv64imafdc_zicsr_zifencei_zba_zbb_zbc_zbs -- note
that `rv64g` is an alias for `rv64imafd`.

This allows the usage of the bit manipulation extension instructions
with the widely used "G" (general purpose computing) ISA.

Signed-off-by: Stephanos Ioannidis <root@stephanos.io>

Author: stephanosio

gcc/config/riscv/t-zephyr

@@ -42,6 +42,7 @@ MULTILIB_SRC_ARCH += rv64imac_zicsr_zifencei
 MULTILIB_SRC_ARCH += rv64imac_zicsr_zifencei_zba_zbb_zbc_zbs
 MULTILIB_SRC_ARCH += rv64imafd_zicsr_zifencei
 MULTILIB_SRC_ARCH += rv64imafdc_zicsr_zifencei
+MULTILIB_SRC_ARCH += rv64imafdc_zicsr_zifencei_zba_zbb_zbc_zbs
 MULTILIB_SRC_ARCH += rv64imc_zicsr_zifencei
 MULTILIB_SRC_ARCH += rv64imc_zicsr_zifencei_zba_zbb_zbc_zbs
 MULTILIB_SRC_ARCH += rv64imfc_zicsr_zifencei
@@ -51,6 +52,7 @@ MULTILIB_SRC_ARCH += rv64iac_zicsr_zifencei
 MULTILIB_SRC_ARCH += rv64ic_zicsr_zifencei
 MULTILIB_SRC_ARCH += rv64g
 MULTILIB_SRC_ARCH += rv64gc
+MULTILIB_SRC_ARCH += rv64gc_zba_zbb_zbc_zbs
 
 MULTILIB_SRC_ABI  = ilp32
 MULTILIB_SRC_ABI += ilp32f
@@ -85,6 +87,7 @@ march=rv64im_zicsr_zifencei_zba_zbb_zbc_zbs/mabi=lp64/mcmodel=medany \
 march=rv64imac_zicsr_zifencei/mabi=lp64/mcmodel=medany \
 march=rv64imac_zicsr_zifencei_zba_zbb_zbc_zbs/mabi=lp64/mcmodel=medany \
 march=rv64imafdc_zicsr_zifencei/mabi=lp64d/mcmodel=medany \
+march=rv64imafdc_zicsr_zifencei_zba_zbb_zbc_zbs/mabi=lp64d/mcmodel=medany \
 march=rv64imafd_zicsr_zifencei/mabi=lp64d/mcmodel=medany \
 march=rv64imfc_zicsr_zifencei/mabi=lp64f/mcmodel=medany \
 march=rv64imfc_zicsr_zifencei_zba_zbb_zbc_zbs/mabi=lp64f/mcmodel=medany
@@ -117,6 +120,7 @@ march.rv64im_zicsr_zifencei_zba_zbb_zbc_zbs/mabi.lp64/mcmodel.medany=march.rv64i
 march.rv64imac_zicsr_zifencei/mabi.lp64/mcmodel.medany=march.rv64imac_zicsr_zifencei/mabi.lp64 \
 march.rv64imac_zicsr_zifencei_zba_zbb_zbc_zbs/mabi.lp64/mcmodel.medany=march.rv64imac_zicsr_zifencei_zba_zbb_zbc_zbs/mabi.lp64 \
 march.rv64imafdc_zicsr_zifencei/mabi.lp64d/mcmodel.medany=march.rv64imafdc_zicsr_zifencei/mabi.lp64d \
+march.rv64imafdc_zicsr_zifencei_zba_zbb_zbc_zbs/mabi.lp64d/mcmodel.medany=march.rv64imafdc_zicsr_zifencei_zba_zbb_zbc_zbs/mabi.lp64d \
 march.rv64imafd_zicsr_zifencei/mabi.lp64d/mcmodel.medany=march.rv64imafd_zicsr_zifencei/mabi.lp64d \
 march.rv64imfc_zicsr_zifencei/mabi.lp64f/mcmodel.medany=march.rv64imfc_zicsr_zifencei/mabi.lp64f \
 march.rv64i_zicsr_zifencei/mabi.lp64/mcmodel.medany=march.rv64ia_zicsr_zifencei/mabi.lp64/mcmodel.medany \
@@ -135,6 +139,8 @@ march.rv64im_zicsr_zifencei_zba_zbb_zbc_zbs/mabi.lp64/mcmodel.medany=march.rv64i
 march.rv64im_zicsr_zifencei_zba_zbb_zbc_zbs/mabi.lp64/mcmodel.medany=march.rv64imc_zicsr_zifencei_zba_zbb_zbc_zbs/mabi.lp64 \
 march.rv64imafdc_zicsr_zifencei/mabi.lp64d/mcmodel.medany=march.rv64gc/mabi.lp64d/mcmodel.medany \
 march.rv64imafdc_zicsr_zifencei/mabi.lp64d/mcmodel.medany=march.rv64gc/mabi.lp64d \
+march.rv64imafdc_zicsr_zifencei_zba_zbb_zbc_zbs/mabi.lp64d/mcmodel.medany=march.rv64gc_zba_zbb_zbc_zbs/mabi.lp64d/mcmodel.medany \
+march.rv64imafdc_zicsr_zifencei_zba_zbb_zbc_zbs/mabi.lp64d/mcmodel.medany=march.rv64gc_zba_zbb_zbc_zbs/mabi.lp64d \
 march.rv64imafd_zicsr_zifencei/mabi.lp64d/mcmodel.medany=march.rv64g/mabi.lp64d/mcmodel.medany \
 march.rv64imafd_zicsr_zifencei/mabi.lp64d/mcmodel.medany=march.rv64g/mabi.lp64d