Improve README.md for installation and issue

README.md

@@ -56,12 +56,18 @@ Raspberry Pi 2/3/4 with GNU/Linux.
 ## Prerequisites
 * Code generator in AMaCC relies on several GNU/Linux behaviors, and it
   is necessary to have Arm/Linux installed in your build environment.
+* Throughout this document, Ubuntu - Debian based Linux - on x86 PC is used as an
+  example. If other Linux distro is used, Linux shell command needs to be
+  modified accordingly. For example, changing `apt-get` to `yum` for CentOS.
 * Install [GNU Toolchain for the A-profile Architecture](https://developer.arm.com/tools-and-software/open-source-software/developer-tools/gnu-toolchain/gnu-a/downloads)
     - Select `arm-linux-none-gnueabihf` (AArch32 target with hard float)
+```shell 
+$ sudo apt-get install gcc-arm-linux-gnueabihf 
+```
 
 * Install QEMU for Arm user emulation
 ```shell
-sudo apt-get install qemu-user
+$ sudo apt-get install qemu-user
 ```
 
 ## Running AMaCC
@@ -80,6 +86,33 @@ OK
 
 Check the messages generated by `make help` to learn more.
 
+## Potential Issues Running AMaCC
+There might be issue related to link path setting, error message `/lib/ld-linux-armhf.so.3: No such file or directory` like below.
+```
+$ make clean
+rm -f amacc amacc-native elf/* elf/* out-gcc/*
+$ make
+  CC+LD   amacc
+  CC+LD   amacc-native
+$ qemu-arm ./amacc tests/hello.c
+/lib/ld-linux-armhf.so.3: No such file or directory
+```
+
+It can be solved by either of the following options.
+```
+# option 1 - using '-L' option
+$ qemu-arm -L /usr/arm-linux-gnueabihf/ ./amacc tests/hello.c
+hello, world
+
+# option 2 - set QEMU_LD_PREFIX path
+$ export QEMU_LD_PREFIX=/usr/arm-linux-gnueabihf
+$ echo $QEMU_LD_PREFIX
+/usr/arm-linux-gnueabihf
+$ qemu-arm ./amacc tests/hello.c
+hello, world
+```
+
+
 ## Benchmark
 AMaCC is able to generate machine code really fast and provides 70% of the performance of `gcc -O0`.
 
@@ -106,3 +139,4 @@ AMaCC is based on the infrastructure of [c4](https://github.com/rswier/c4).
 * [Curated list of awesome resources on Compilers, Interpreters and Runtimes](http://aalhour.com/awesome-compilers/)
 * [Hacker News discussions](https://news.ycombinator.com/item?id=11411124)
 * [A Compiler Writing Journey](https://github.com/DoctorWkt/acwj) by Warren Toomey.
+* [How to solve "error while loading shared libraries" when trying to run an arm binary with qemu-arm?](https://stackoverflow.com/questions/16158994/how-to-solve-error-while-loading-shared-libraries-when-trying-to-run-an-arm-bi)