Document how to pass additional compiler and linker flags

Author: jonas

README.md

@@ -89,6 +89,14 @@ To build a statically linked executable pass `-DSTATIC_LINKING=ON` when invoking
 cmake -DSTATIC_LINKING=ON ..
 ```
 
+Additional compiler and linker flags may be passed as environment variable sor their CMake
+equivalent, e.g. to compile with debug symbols the following are the same:
+
+```sh
+cmake -DCMAKE_CXX_FLAGS=-g ..
+CXXFLAGS=-g cmake ..
+```
+
 ### Building with `docker-compose`
 
 Alternatively, you can use [docker-compose] to build and test the program:

bindgen/Main.cpp

@@ -3,7 +3,7 @@
 #include <clang/Tooling/CommonOptionsParser.h>
 
 int main(int argc, const char *argv[]) {
-    llvm::cl::OptionCategory Category("Binding Generator");
+    llvm::cl::OptionCategory Category("Scala Native Binding Generator");
     llvm::cl::extrahelp CommonHelp(
         clang::tooling::CommonOptionsParser::HelpMessage);
     llvm::cl::extrahelp MoreHelp("\nProduce Bindings for scala native. Please "