[PATCH] config: Fix -rdynamic detection for libcc1 usage

[Goncharov Mark]

Trying to compile libcc1 plugin in native RISC-V GCC build on X86
I bumped into the problem that gcc_cv_objdump variable
was not defined in libcc1/configure, because it has definition
only in gcc/configure.ac.

In my case, it leads to problem that -rdynamic check is failed
and it disables libcc1 build.

I propose to use libtool inferred variable for common configs.
---
 config/gcc-plugin.m4 | 6 +++++-
 gcc/configure        | 6 +++++-
 libcc1/configure     | 6 +++++-
 3 files changed, 15 insertions(+), 3 deletions(-)

diff --git a/config/gcc-plugin.m4 b/config/gcc-plugin.m4
index c30cfdd8fad..5c59bdddc28 100644
--- a/config/gcc-plugin.m4
+++ b/config/gcc-plugin.m4
@@ -47,7 +47,11 @@ AC_DEFUN([GCC_ENABLE_PLUGINS],
        if test x$build = x$host; then
         export_sym_check="$ac_cv_prog_OBJDUMP -T"
        elif test x$host = x$target; then
-        export_sym_check="$gcc_cv_objdump -T"
+         if test x$gcc_cv_objdump != x; then
+          export_sym_check="$gcc_cv_objdump -T"
+         else
+          export_sym_check="$ac_cv_prog_OBJDUMP -T"
+         fi
        else
         export_sym_check="$ac_cv_prog_OBJDUMP -T"
        fi
diff --git a/gcc/configure b/gcc/configure
index b4c52de6218..d69eb1746a6 100755
--- a/gcc/configure
+++ b/gcc/configure
@@ -34106,7 +34106,11 @@ fi
        if test x$build = x$host; then
         export_sym_check="$ac_cv_prog_OBJDUMP -T"
        elif test x$host = x$target; then
-        export_sym_check="$gcc_cv_objdump -T"
+         if test x$gcc_cv_objdump != x; then
+          export_sym_check="$gcc_cv_objdump -T"
+         else
+          export_sym_check="$ac_cv_prog_OBJDUMP -T"
+         fi
        else
         export_sym_check="$ac_cv_prog_OBJDUMP -T"
        fi
diff --git a/libcc1/configure b/libcc1/configure
index ea689a353c8..82fc9674543 100755
--- a/libcc1/configure
+++ b/libcc1/configure
@@ -15220,7 +15220,11 @@ fi
        if test x$build = x$host; then
         export_sym_check="$ac_cv_prog_OBJDUMP -T"
        elif test x$host = x$target; then
-        export_sym_check="$gcc_cv_objdump -T"
+         if test x$gcc_cv_objdump != x; then
+          export_sym_check="$gcc_cv_objdump -T"
+         else
+          export_sym_check="$ac_cv_prog_OBJDUMP -T"
+         fi
        else
         export_sym_check="$ac_cv_prog_OBJDUMP -T"
        fi
-- 
2.43.0