[libc]新建gcc文件夹，将newlib和partical文件夹并入

components/libc/compilers/gcc/newlib/SConscript

@@ -0,0 +1,28 @@
+from building import *
+Import('rtconfig')
+
+src = []
+cwd = GetCurrentDir()
+group = []
+LIBS = []
+CPPDEFINES = []
+CPPPATH = [cwd]
+
+if rtconfig.PLATFORM == 'gcc':
+    if GetDepend('RT_USING_LIBC'):
+        CPPDEFINES += ['RT_USING_NEWLIB']
+        # link with libc and libm:
+        # libm is a frequently used lib. Newlib is compiled with -ffunction-sections in
+        # recent GCC tool chains. The linker would just link in the functions that have
+        # been referenced. So setting this won't result in bigger text size.
+        LIBS += ['c', 'm']
+
+        src += Glob('*.c')
+        if GetDepend('RT_USING_MODULE') == False:
+            SrcRemove(src, ['libc_syms.c'])
+    else:
+        src += ['syscalls.c']
+
+    group = DefineGroup('libc', src, depend = [], CPPPATH = CPPPATH, CPPDEFINES = CPPDEFINES, LIBS = LIBS)
+
+Return('group')