Update INSTALL.md

Author: lahiri-phdworks

clang-fe/INSTALL.md

@@ -7,8 +7,14 @@ First get the dependencies
 
 On Ubuntu, run `sudo apt-get install llvm-7 libllvm7 clang-7`
 
+## Missing Clang `Headers` :
+
+```bash 
+sudo apt-get install libclang-7-dev
+```
+
 Get them at http://clang.llvm.org/get_started.html
 
 Then run `make` while inside the clang-fe directory. This should make an executable named ssa-transform.
 
-You may need to edit the include variables of `make` if llvm-config-7 does not include the clang include directory or produces linker errors.
+You may need to edit the include variables of `make` if llvm-config-7 does not include the clang include directory or produces linker errors.