configure: Add --enable-debuginfo

configure

@@ -535,6 +535,7 @@ opt optimize-tests 1 "build tests with optimizations"
 opt libcpp 1 "build with llvm with libc++ instead of libstdc++ when using clang"
 opt llvm-assertions 0 "build LLVM with assertions"
 opt debug-assertions 0 "build with debugging assertions"
+opt debuginfo 0 "build with debugger metadata"
 opt fast-make 0 "use .gitmodules as timestamp for submodule deps"
 opt ccache 0 "invoke gcc/clang via ccache to reuse object files between builds"
 opt local-rust 0 "use an installed rustc rather than downloading a snapshot"

mk/main.mk

@@ -133,6 +133,11 @@ else
   CFG_RUSTC_FLAGS += --cfg ndebug
 endif
 
+ifdef CFG_ENABLE_DEBUGINFO
+  $(info cfg: enabling debuginfo (CFG_ENABLE_DEBUGINFO))
+  CFG_RUSTC_FLAGS += -g
+endif
+
 ifdef SAVE_TEMPS
   CFG_RUSTC_FLAGS += --save-temps
 endif