按照常规教程 codesign 之后，gdb仍然提示：
Unable to find Mach task port for process-id 39847: (os/kern) failure (0x5).\n (please check gdb is codesigned - see taskgated(8))
解决参考：
macOS Mojave: How to achieve codesign to enable debugging (gdb)?
https://stackoverflow.com/questions/52699661/macos-mojave-how-to-achieve-codesign-to-enable-debugging-gdb
This is related to codesign entitlements. you must add "com.apple.security.cs.debugger" key in signing process.
for example you must change codesign -fs gdb-cert /usr/local/bin/gdb to codesign --entitlements gdb.xml -fs gdbcert /usr/local/bin/gdb .
gdb.xml content must something like following code.
com.apple.security.cs.debugger
注：如果要取消对gdb的证书签名，可以使用 codesign --remove-signature /usr/local/bin/gdb 来完成，前提是你的gdb-cert签名还在。
另外一个 error，gdb>run
During startup program terminated with signal ?, Unknown signal.
目前稳定版无解：最终选择使用 git 开发版：gdb-8.3.50.20190401.tar.xz
下载地址：ftp://sourceware.org/pub/gdb/snapshots/current/gdb-8.3.50.20190401.tar.xz
安装完成： GDB 版本：GNU gdb (GDB) 8.3.50.20190401-git
解决参考：
GDB errors on macOS Mojave
https://stackoverflow.com/questions/54736753/gdb-errors-on-macos-mojave
OK，gdb！