cmake:init RISC-V cmake qemu-rv build

cmake currently does not support non-FlatBuild,
need disable ELF and LOADABLE when compiling other defconfigs

```
 cmake -B build -DBOARD_CONFIG=rv-virt/smp64 -GNinja # for rv32:rv-virt/smp
 cmake --build build -t menuconfig
 cmake --build build
 qemu-system-riscv64 -semihosting -M virt,aclint=on -cpu rv64 -smp 8 -bios none -kernel nuttx -nographic
```

Signed-off-by: xuxin19 <xuxin19@xiaomi.com>

libs/libc/machine/risc-v/CMakeLists.txt

@@ -17,7 +17,7 @@
 # the License.
 #
 # ##############################################################################
-add_subdirectory(common)
+add_subdirectory(gnu)
 
 if(CONFIG_ARCH_RV64GC)
   add_subdirectory(rv64)
@@ -26,3 +26,11 @@ endif()
 if(CONFIG_ARCH_RV32IM)
   add_subdirectory(rv32)
 endif()
+
+set(SRCS)
+
+if(CONFIG_LIBC_ARCH_ELF)
+  list(APPEND SRCS arch_elf.c)
+endif()
+
+target_sources(c PRIVATE ${SRCS})

libs/libc/machine/risc-v/common/CMakeLists.txt

@@ -17,14 +17,3 @@
 # the License.
 #
 # ##############################################################################
-set(SRCS)
-
-if(CONFIG_LIBC_ARCH_ELF)
-  list(APPEND SRCS arch_elf.c)
-endif()
-
-if(CONFIG_ARCH_SETJMP_H)
-  list(APPEND SRCS arch_setjmp.S)
-endif()
-
-target_sources(c PRIVATE ${SRCS})

libs/libc/machine/risc-v/gnu/CMakeLists.txt

@@ -0,0 +1,39 @@
+# ##############################################################################
+# libs/libc/machine/risc-v/gnu/CMakeLists.txt
+#
+# Licensed to the Apache Software Foundation (ASF) under one or more contributor
+# license agreements.  See the NOTICE file distributed with this work for
+# additional information regarding copyright ownership.  The ASF licenses this
+# file to you under the Apache License, Version 2.0 (the "License"); you may not
+# use this file except in compliance with the License.  You may obtain a copy of
+# the License at
+#
+# http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.  See the
+# License for the specific language governing permissions and limitations under
+# the License.
+#
+# ##############################################################################
+
+set(SRCS)
+
+if(CONFIG_RISCV_MEMCPY)
+  list(APPEND SRCS arch_memcpy.S)
+endif()
+
+if(CONFIG_RISCV_MEMSET)
+  list(APPEND SRCS arch_memset.S)
+endif()
+
+if(CONFIG_RISCV_STRCMP)
+  list(APPEND SRCS arch_strcmp.S)
+endif()
+
+if(CONFIG_ARCH_SETJMP_H)
+  list(APPEND SRCS arch_setjmp.S)
+endif()
+
+target_sources(c PRIVATE ${SRCS})

libs/libc/machine/risc-v/rv32/CMakeLists.txt

@@ -17,6 +17,3 @@
 # the License.
 #
 # ##############################################################################
-if(CONFIG_RISCV_MEMCPY)
-  target_sources(c PRIVATE arch_memcpy.S)
-endif()