Update README.md (#3374)

improving a bit the doc
- Adding per-requisites and setup info
- Specify proper build instruction (needs to be inside x64 Native Tools for VS)

Author: 20urc3

fuzzers/binary_only/frida_windows_gdiplus/README.md

@@ -3,14 +3,25 @@
 This is a an example how to fuzz binary-only dlls on Windows.
 The example fuzzer will explore [gdiplus](https://learn.microsoft.com/en-us/windows/win32/gdiplus/-gdiplus-gdi-start) on Windows, using the [Frida](https://frida.re/) DBI.
 
+## Pre-requisites
+1. This example depends on the msvc linker `link.exe`, ensure that Visual Studio 2017 (or later) or Build Tools for Visual Studio were installed with the Visual C++ option.
+2. `libclang` must be installed for `frida-gum` to work, download the latest compatible clang release and set the envrionment path `LIBCLANG_PATH` by using setx LIBCLANG_PATH "path/to/libclang.dll_folder/"
+
+
 ## Build
 
-To build this example, run `cargo build --release` in this folder.
+To build this example:
+1. Open `x64 Native Tools Command Prompt for VS 2022 Preview` and cd into this example folder.
+2. run `cargo build --release` in this folder.
+4. Compile the harness `cl.exe /LD harness.cc /link /dll gdiplus.lib ole32.lib`
 
-Then compile the harness `cl.exe /LD harness.cc /link /dll gdiplus.lib ole32.lib`
+Note: this fuzzer is **statically linked** with C runtime. This is achieved by specifying `rustflags = ["-C", "target-feature=+crt-static"]` in `.cargo/config.toml`. 
 
-Note: this fuzzer is **statically linked** with C runtime. This is achieved by specifying `rustflags = ["-C", "target-feature=+crt-static"]` in `.cargo/config.toml`. The static linking is necessary to avoid Asan function hooks to hook the calls from the fuzzer itself, as such self-hooking can eventually lead to deadlocks in internal Frida mechanisms.
+The static linking is necessary to avoid Asan function hooks to hook the calls from the fuzzer itself, as such self-hooking can eventually lead to deadlocks in internal Frida mechanisms.
 
 ## Run
 
-To run the example `target\release\frida_windows_gdiplus.exe -H harness.dll -i corpus -o output --libs-to-instrument gdi32.dll --libs-to-instrument gdi32full.dll --libs-to-instrument gdiplus.dll --libs-to-instrument WindowsCodecs.dll --disable-excludes`
+To run the example: 
+```
+target\release\frida_windows_gdiplus.exe -H harness.dll -i corpus -o output --libs-to-instrument gdi32.dll --libs-to-instrument gdi32full.dll --libs-to-instrument gdiplus.dll --libs-to-instrument WindowsCodecs.dll --disable-excludes
+```