Adding compilation_db to panda builds (#1828)

SConscript

@@ -101,7 +101,8 @@ def build_project(project_name, project, extra_flags):
     ASCOM="$AS $ASFLAGS -o $TARGET -c $SOURCES",
     BUILDERS={
       'Objcopy': Builder(generator=objcopy, suffix='.bin', src_suffix='.elf')
-    }
+    },
+    tools=["default", "compilation_db"],
   )
 
   startup = env.Object(f"obj/startup_{project_name}", project["STARTUP_FILE"])

SConstruct

@@ -12,5 +12,17 @@ AddOption('--coverage',
           action='store_true',
           help='build with test coverage options')
 
+AddOption('--compile_db',
+          action='store_true',
+          help='build clang compilation database')
+
+env = Environment(
+  COMPILATIONDB_USE_ABSPATH=True,
+  tools=["default", "compilation_db"],
+)
+  
+if GetOption('compile_db'):
+    env.CompilationDatabase("compile_commands.json")
+
 # panda fw & test files
 SConscript('SConscript')