contrib/plugins: enable debug on CONFIG_DEBUG_TCG

We used to rely on QEMU_CFLAGS to expose the debug flags but now this
is synthesised by meson and only available to the main build. Add our
own flags if we detect the build has been enabled with
CONFIG_DEBUG_TCG (which is the default for --enable-debug anyway).

Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Message-Id: <20221027183637.2772968-28-alex.bennee@linaro.org>

contrib/plugins/Makefile

@@ -29,6 +29,7 @@ SONAMES := $(addsuffix .so,$(addprefix lib,$(NAMES)))
 CFLAGS = $(GLIB_CFLAGS)
 CFLAGS += -fPIC -Wall $(filter -W%, $(QEMU_CFLAGS))
 CFLAGS += $(if $(findstring no-psabi,$(QEMU_CFLAGS)),-Wpsabi)
+CFLAGS += $(if $(CONFIG_DEBUG_TCG), -ggdb -O0)
 CFLAGS += -I$(SRC_PATH)/include/qemu
 
 all: $(SONAMES)