docs: add troubleshooting steps for naabu (libpcap-dev required)

README.md

@@ -91,6 +91,33 @@ DEBUG:
    -v, -verbose             show verbose output
    -nc, -no-color           disable output content coloring (ANSI escape codes)
    -disable-changelog, -dc  disable release changelog in output
+
+#### Troubleshooting `naabu` source builds (pcap.h error)
+
When `pdtm` installs **naabu** via `go install` (source build), **libpcap
+development headers** are required. 
+If they’re missing, the build will fail with:
+
```bash
+fatal error: pcap.h: No such file or directory
+```
+
**Install prerequisites by distro:**
+
- **Debian / Ubuntu / Kali**
+```bash
+sudo apt update
+sudo apt install -y libpcap-dev build-essential
+```
+
- **Fedora / RHEL**
+```bash
+sudo dnf install -y libpcap-devel @development-tools
+```
+
- **Arch Linux**
+```bash
+sudo pacman -S --needed libpcap base-devel
+```
+
**Optional:** Allow `naabu` to run without sudo 
+```bash
+sudo setcap cap_net_raw,cap_net_admin=eip "$(which naabu)"
+
+
 ```
 
 ## Running pdtm