Allow modules to specify defines

The modules.yaml now has an optional defines: list per module that adds
preprocessor definitions to the build scripts. Also added a --debug flag
to qemu.sh to run QEMU's debugger host.

generate_build.py

@@ -33,6 +33,7 @@ class Module:
         self.target = kwargs.get("target", None)
         self.deps = kwargs.get("deps", tuple())
         self.includes = kwargs.get("includes", tuple())
+        self.defines = kwargs.get("defines", tuple())
         self.depmods = []
 
         sources = [join(root, f) for f in kwargs.get("source", tuple())]

qemu.sh

@@ -1,5 +1,11 @@
 #!/usr/bin/env bash
 
+debug=""
+if [[ $1 = "--debug" ]]; then
+	debug="-s"
+	shift
+fi
+
 build=${1:-"$(dirname $0)/build"}
 
 kvm=""
@@ -19,4 +25,4 @@ exec qemu-system-x86_64 \
 	-M q35 \
 	-no-reboot \
 	-nographic \
-	$kvm
+	$kvm $debug

scripts/templates/module.base.j2

@@ -10,6 +10,9 @@ ccflags = $ccflags $
     {%- for inc in module.includes %}
     -I${srcroot}/{{ inc }} $
     {%- endfor %}
+    {%- for define in module.defines %}
+    -D{{ define }} $
+    {%- endfor %}
 {% endblock %}
 
 {% for source in module.sources %}