debug/gdb: add extra config for gdb cross.

Signed-off-by: Zhenqiang Chen <zhenqiang.chen@linaro.org>
[yann.morin.1998@anciens.enib.fr: prompt rewording, as suggested by M. Hope]
Signed-off-by: "Yann E. MORIN" <yann.morin.1998@anciens.enib.fr>

config/debug/gdb.in.cross

@@ -38,5 +38,12 @@ config GDB_CROSS_PYTHON
       Building a static gdb can help in this regard, although there
       have been reports of problems when linking gdb to the static
       libpython.a. This should be fixed in gdb >=7.3. YMMV.
-      
+
+config GDB_CROSS_EXTRA_CONFIG_ARRAY
+    string
+    prompt "Cross-gdb extra config"
+    default ""
+    help
+      Extra flags to pass onto ./configure when configuring the gdb cross.
+
 endif # GDB_CROSS

scripts/build/debug/300-gdb.sh

@@ -147,7 +147,8 @@ do_debug_gdb_build() {
             --with-sysroot="${CT_SYSROOT_DIR}"          \
             --with-expat=yes                            \
             --disable-werror                            \
-            "${cross_extra_config[@]}"
+            "${cross_extra_config[@]}"                  \
+            "${CT_GDB_CROSS_EXTRA_CONFIG_ARRAY[@]}"
 
         CT_DoLog EXTRA "Building cross-gdb"
         CT_DoExecLog ALL make ${JOBSFLAGS}