Add option to build Ada debugging code

Ada knows a pragma `Debug` that is used to exclude procedure calls from
a release build. The new option `DEBUG_ADA_CODE` enables those procedure
calls.

Change-Id: Id5298e5819606c3d1cf2a2a1cd4f1d5d1227aa4f
Signed-off-by: Nico Huber <nico.huber@secunet.com>
Reviewed-on: https://review.coreboot.org/16943
Tested-by: build bot (Jenkins)
Reviewed-by: Martin Roth <martinroth@google.com>

Makefile.inc

@@ -420,6 +420,10 @@ CFLAGS_common += -Os
 ADAFLAGS_common += -Os
 endif
 
+ifeq ($(CONFIG_DEBUG_ADA_CODE),y)
+ADAFLAGS_common += -gnata
+endif
+
 additional-dirs := $(objutil)/cbfstool $(objutil)/romcc $(objutil)/ifdtool \
 		   $(objutil)/ifdfake $(objutil)/options $(obj)/amdfwtool \
 		   $(objutil)/cbootimage $(objutil)/bimgtool

src/Kconfig

@@ -1135,6 +1135,13 @@ config DEBUG_PRINT_PAGE_TABLES
 	  After the page tables have been built, print them on the debug
 	  console.
 
+config DEBUG_ADA_CODE
+	bool "Compile debug code in Ada sources"
+	default n
+	help
+	  Add the compiler switch `-gnata` to compile code guarded by
+	  `pragma Debug`.
+
 endmenu
 
 # These probably belong somewhere else, but they are needed somewhere.