【记录一个问题】libtask无法在android下编译通过

源码来自：https://github.com/msteinert/libtask

首先是asm.S无法编译通过。
其次，编译context.c出现这些错误：

.//context.c:124:19: error: no member named 'gregs' in 'struct sigcontext'; did you mean 'regs'?
                uc->uc_mcontext.gregs[i] = va_arg(arg, uint);
                                ^~~~~
                                regs
/Users/ahfu/code/android/android-ndk-r14b/platforms/android-21/arch-arm64/usr/include/asm/sigcontext.h:25:8: note: 'regs' declared here
 __u64 regs[31];
       ^
.//context.c:127:18: error: no member named 'gregs' in 'struct sigcontext'; did you mean 'regs'?
        uc->uc_mcontext.gregs[13] = (uint)sp;
                        ^~~~~
                        regs
/Users/ahfu/code/android/android-ndk-r14b/platforms/android-21/arch-arm64/usr/include/asm/sigcontext.h:25:8: note: 'regs' declared here
 __u64 regs[31];
       ^
.//context.c:128:18: error: no member named 'gregs' in 'struct sigcontext'; did you mean 'regs'?
        uc->uc_mcontext.gregs[14] = (uint)fn;
                        ^~~~~
                        regs
/Users/ahfu/code/android/android-ndk-r14b/platforms/android-21/arch-arm64/usr/include/asm/sigcontext.h:25:8: note: 'regs' declared here
 __u64 regs[31];
       ^
3 errors generated.

=====================================
2019-08-01:
原因大致确定：
context.c需要的寄存器结构，是arm 64下面的；
asm.S的语法是arm 32下面的。