make __socketcall analogous to __syscall, error-returning

the __socketcall and __socketcall_cp macros are remnants from a really
old version of the syscall-mechanism infrastructure, and don't follow
the pattern that the "__" version of the macro returns the raw negated
error number rather than setting errno and returning -1.

for time64 purposes, some socket syscalls will need to operate on the
error value rather than returning immediately, so fix this up so they
can use it.

src/internal/syscall.h

@@ -43,8 +43,8 @@ hidden long __syscall_ret(unsigned long),
 #define __syscall(...) __SYSCALL_DISP(__syscall,__VA_ARGS__)
 #define syscall(...) __syscall_ret(__syscall(__VA_ARGS__))
 
-#define socketcall __socketcall
-#define socketcall_cp __socketcall_cp
+#define socketcall(nm,a,b,c,d,e,f) __syscall_ret(__socketcall(nm,a,b,c,d,e,f))
+#define socketcall_cp(nm,a,b,c,d,e,f) __syscall_ret(__socketcall_cp(nm,a,b,c,d,e,f))
 
 #define __syscall_cp0(n) (__syscall_cp)(n,0,0,0,0,0,0)
 #define __syscall_cp1(n,a) (__syscall_cp)(n,__scc(a),0,0,0,0,0)
@@ -58,12 +58,12 @@ hidden long __syscall_ret(unsigned long),
 #define syscall_cp(...) __syscall_ret(__syscall_cp(__VA_ARGS__))
 
 #ifndef SYSCALL_USE_SOCKETCALL
-#define __socketcall(nm,a,b,c,d,e,f) syscall(SYS_##nm, a, b, c, d, e, f)
-#define __socketcall_cp(nm,a,b,c,d,e,f) syscall_cp(SYS_##nm, a, b, c, d, e, f)
+#define __socketcall(nm,a,b,c,d,e,f) __syscall(SYS_##nm, a, b, c, d, e, f)
+#define __socketcall_cp(nm,a,b,c,d,e,f) __syscall_cp(SYS_##nm, a, b, c, d, e, f)
 #else
-#define __socketcall(nm,a,b,c,d,e,f) syscall(SYS_socketcall, __SC_##nm, \
+#define __socketcall(nm,a,b,c,d,e,f) __syscall(SYS_socketcall, __SC_##nm, \
     ((long [6]){ (long)a, (long)b, (long)c, (long)d, (long)e, (long)f }))
-#define __socketcall_cp(nm,a,b,c,d,e,f) syscall_cp(SYS_socketcall, __SC_##nm, \
+#define __socketcall_cp(nm,a,b,c,d,e,f) __syscall_cp(SYS_socketcall, __SC_##nm, \
     ((long [6]){ (long)a, (long)b, (long)c, (long)d, (long)e, (long)f }))
 #endif