dev-util/mingw64-toolchain: fix direct objdump call

Cherry pick from Gentoo's gcc patches. Ideally don't want to
carry/follow the full set given they do not really affect this
(features are disabled, or irrelevant with mingw target), but
this one does.

Turns out plugin is silently skipped entirely if objdump is missing.

Bug: https://bugs.gentoo.org/843989
Signed-off-by: Ionen Wolkens <ionen@gentoo.org>

dev-util/mingw64-toolchain/files/gcc-11.3.0-plugin-objdump.patch

@@ -0,0 +1,22 @@
+https://gcc.gnu.org/PR95648
+--- a/gcc/config/gcc-plugin.m4
++++ b/gcc/config/gcc-plugin.m4
+@@ -47,3 +47,3 @@
+        if test x$build = x$host; then
+-	 export_sym_check="objdump${exeext} -T"
++	 export_sym_check="$ac_cv_prog_OBJDUMP -T"
+        elif test x$host = x$target; then
+--- a/gcc/gcc/configure
++++ b/gcc/gcc/configure
+@@ -32069,3 +32069,3 @@
+        if test x$build = x$host; then
+-	 export_sym_check="objdump${exeext} -T"
++	 export_sym_check="$ac_cv_prog_OBJDUMP -T"
+        elif test x$host = x$target; then
+--- a/gcc/libcc1/configure
++++ b/gcc/libcc1/configure
+@@ -15017,3 +15017,3 @@
+        if test x$build = x$host; then
+-	 export_sym_check="objdump${exeext} -T"
++	 export_sym_check="$ac_cv_prog_OBJDUMP -T"
+        elif test x$host = x$target; then

dev-util/mingw64-toolchain/mingw64-toolchain-10.0.0.ebuild

@@ -43,6 +43,7 @@ DEPEND="${RDEPEND}"
 
 PATCHES=(
 	"${FILESDIR}"/mingw64-runtime-10.0.0-tmp-files-clash.patch
+	"${FILESDIR}"/gcc-11.3.0-plugin-objdump.patch
 )
 
 pkg_pretend() {