package/gdb: build and link libbfd and libopcodes as static libraries

Since GDB 13.x and upstream commit
b686ecb5b10be9a33ab8f1bfdcff22eef920d1a5 ("gdb: link executables with
libtool"), gdb will be linked against the shared variants of libbfd
and libopcodes if they exist. However, this causes host gdb and target
gdb to not work, because our gdb package does not install libbfd and
libopcodes (to not clash with the ones potentially installed by
binutils).

In order to get around this, this commit proposes to get back to the
situation we had before GDB 13.x: libbfd and libopcodes are only
compiled as static libraries, so that they are linked directly inside
the gdb binary, avoiding the problem entirely.

This resolves:

 # gdb --version
 gdb: error while loading shared libraries: libopcodes-2.39.50.so: cannot open shared object file: No such file or directory

for target gdb, and:

 $ ./host/bin/arm-linux-gdb --version
 ./host/bin/arm-linux-gdb: error while loading shared libraries: libopcodes-2.39.50.so: cannot open shared object file: No such file or directory

for host gdb.

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
Signed-off-by: Yann E. MORIN <yann.morin.1998@free.fr>

package/gdb/gdb.mk

@@ -121,8 +121,10 @@ GDB_MAKE_ENV += \
 GDB_CONF_ENV += gdb_cv_prfpregset_t_broken=no
 GDB_MAKE_ENV += gdb_cv_prfpregset_t_broken=no
 
-# The shared only build is not supported by gdb, so enable static build for
-# build-in libraries with --enable-static.
+# We want the built-in libraries of gdb (libbfd, libopcodes) to be
+# built and linked statically, as we do not install them on the
+# target, to not clash with the ones potentially installed by
+# binutils. This is why we pass --enable-static --disable-shared.
 GDB_CONF_OPTS = \
 	--without-uiout \
 	--disable-gdbtk \
@@ -132,6 +134,7 @@ GDB_CONF_OPTS = \
 	--without-included-gettext \
 	--disable-werror \
 	--enable-static \
+	--disable-shared \
 	--without-mpfr \
 	--disable-source-highlight
 
@@ -248,10 +251,14 @@ endif
 # A few notes:
 #  * --target, because we're doing a cross build rather than a real
 #    host build.
-#  * --enable-static because gdb really wants to use libbfd.a
+#  * --enable-static --disable-shared because we want host gdb to
+#    build and link against a static version of libbfd and
+#    libopcodes, because we don't install the shared variants of
+#    those libraries in $(HOST_DIR), as it might clash with binutils
 HOST_GDB_CONF_OPTS = \
 	--target=$(GNU_TARGET_NAME) \
 	--enable-static \
+	--disable-shared \
 	--without-uiout \
 	--disable-gdbtk \
 	--without-x \