[posix] POSIX standard implementation for PSE51 (#5384)

* [posix] POSIX standard implementation for PSE51

- add some posix's interfaces that we haven't before.
- these PR have passed the interface definition test across gcc platfrom;
- have tested base on qemu-a9 and stm32h750-art-pi.

* [newlib] only enable POSIX.1-1990

* update projects

components/libc/compilers/gcc/newlib/SConscript

@@ -5,7 +5,6 @@ src = []
 cwd = GetCurrentDir()
 group = []
 LIBS = ['m'] # link libm
-CPPDEFINES = ['RT_USING_NEWLIB']
 CPPPATH = [cwd]
 
 if rtconfig.PLATFORM == 'gcc':
@@ -15,6 +14,9 @@ if rtconfig.PLATFORM == 'gcc':
     else:
         src += ['syscalls.c']
 
+    # identify this is Newlib, and only enable POSIX.1-1990
+    CPPDEFINES = ['RT_USING_NEWLIB', '_POSIX_C_SOURCE=1']
+
     group = DefineGroup('libc', src, depend = [], CPPPATH = CPPPATH, CPPDEFINES = CPPDEFINES, LIBS = LIBS)
 
 Return('group')

components/libc/compilers/gcc/newlib/machine/time.h

@@ -4,9 +4,4 @@
 #include <rtconfig.h>
 #define _CLOCKS_PER_SEC_   RT_TICK_PER_SECOND
 
-#ifdef __SPU__
-#include <sys/_timespec.h>
-int nanosleep (const struct timespec *, struct timespec *);
-#endif
-
 #endif  /* _MACHTIME_H_ */