[Docs] Describe gdbserver lookup issue and a workaround

LLDB uses `dladdr` function to discover the path to liblldb and looks there for lldb-server. However, sometimes this function returns the path to the executable that loaded this dll - lldb-mi executable in this case (see section BUGS of [the function's man](https://man7.org/linux/man-pages/man3/dladdr.3.html)).

Author: tkrasnukha

README.md

@@ -61,4 +61,13 @@ cmake -DLLVM_ENABLE_PROJECTS="clang;lldb;libcxx;libcxxabi" -DCMAKE_INSTALL_PREFI
 // Building lldb-mi
 cmake -DCMAKE_PREFIX_PATH=~/buildspace/llvm-inst/ -DUSE_LLDB_FRAMEWORK=1 -GNinja ..
 
-```
+```
+
+# Notes
+
+On some architectures (e. g. Linux, x86-64), LLDB dinamic library fails to determine its location. That results to inability of locating a gdbserver stub:
+```bash
+process launch failed: unable to locate lldb-server
+```
+
+The workaraund is to set LLDB_DEBUGSERVER_PATH environment variable before running LLDB-MI.