[gdb/testsuite] Fix ctf test-cases on openSUSE Tumbleweed

When running test-case gdb.base/ctf-constvars.exp on openSUSE Tumbleweed (with
system gcc version 12, providing gcc -gctf support, enabling the ctf test-cases
in the gdb testsuite), I run into:
...
(gdb) print vox^M
'vox' has unknown type; cast it to its declared type^M
(gdb) FAIL: gdb.base/ctf-constvars.exp: print vox
...

There are two causes for this:
- the linker flags are missing --ctf-variables, so the information for variable
  vox is missing (reported in PR29468), and
- the executable contains some dwarf2 due to some linked-in glibc objects,
  so the ctf info is ignored (reported in PR29160).

By using:
- -Wl,--ctf-variable,
- -Wl,--strip-debug, and
we can make the test-case and some similar test-cases pass.

Tested on x86_64-linux.

Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=29160
Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=29468

gdb/testsuite/gdb.base/ctf-constvars.exp

@@ -32,9 +32,14 @@ if [skip_ctf_tests] {
 standard_testfile .c
 
 # Using `-gctf` generates full-fledged CTF debug information.
-set opts "additional_flags=-gctf"
+set opts {}
+lappend opts additional_flags=-gctf
+lappend opts ldflags=-Wl,--strip-debug
+lappend opts ldflags=-Wl,--ctf-variables
+lappend opts nowarnings
+
 if { [prepare_for_testing "failed to prepare" ${testfile} \
-	  [list $srcfile] [list $opts nowarnings]] } {
+	  [list $srcfile] $opts] } {
     return 0
 }
 

gdb/testsuite/gdb.base/ctf-ptype.exp

@@ -26,10 +26,14 @@ set gcc_compiled [is_c_compiler_gcc]
 standard_testfile .c
 
 # Using `-gctf` generates full-fledged CTF debug information.
-set opts "additional_flags=-gctf"
+set opts {}
+lappend opts additional_flags=-gctf
+lappend opts ldflags=-Wl,--strip-debug
+lappend opts ldflags=-Wl,--ctf-variables
+lappend opts nowarnings
 
 if { [prepare_for_testing "failed to prepare" ${testfile} \
-	  [list $srcfile] [list $opts nowarnings]] } {
+	  [list $srcfile] $opts] } {
     return 0
 }
 

gdb/testsuite/gdb.base/cvexpr.exp

@@ -491,10 +491,14 @@ proc do_test {dir options} {
     #
 }
 
+set ctf_opts {}
+lappend ctf_opts additional_flags=-gctf
+lappend ctf_opts ldflags=-Wl,--strip-debug
+
 # Build up the set of debug formats for which we will run this test.
 set specs { {dwarf {debug}} }
 if ![skip_ctf_tests] {
-    lappend specs {ctf {"additional_flags=-gctf"}}
+    lappend specs [list ctf $ctf_opts]
 }
 
 # Setup and run the test for each debug format.

gdb/testsuite/gdb.base/whatis.exp

@@ -585,10 +585,15 @@ proc do_test {dir options} {
 	"whatis applied to function with 'void' parameter type"
 }
 
+set ctf_opts {}
+lappend ctf_opts additional_flags=-gctf
+lappend ctf_opts ldflags=-Wl,--strip-debug
+lappend ctf_opts ldflags=-Wl,--ctf-variables
+
 # Build up the set of debug formats for which we will run this test.
 set specs { {dwarf {debug}} }
 if ![skip_ctf_tests] {
-    lappend specs {ctf {"additional_flags=-gctf"}}
+    lappend specs [list ctf $ctf_opts]
 }
 
 # Setup and run the test for each debug format.

gdb/testsuite/gdb.ctf/cross-tu-cyclic.exp

@@ -24,10 +24,15 @@ standard_testfile cross-tu-cyclic-1.c  cross-tu-cyclic-2.c \
 	cross-tu-cyclic-3.c  cross-tu-cyclic-4.c
 
 # Using `-gctf` generates full-fledged CTF debug information.
-set opts "additional_flags=-gctf -Wl,--export-dynamic"
+set opts {}
+lappend opts additional_flags=-gctf
+lappend opts ldflags=-Wl,--export-dynamic
+lappend opts ldflags=-Wl,--strip-debug
+lappend opts nowarning
+
 if { [prepare_for_testing "failed to prepare" ${testfile} \
 	  [list $srcfile $srcfile2 $srcfile3 $srcfile4] \
-	  [list $opts nowarnings]] } {
+	  $opts] } {
     return 0
 }
 

gdb/testsuite/gdb.ctf/funcreturn.exp

@@ -30,10 +30,14 @@ set gcc_compiled [is_c_compiler_gcc]
 standard_testfile whatis.c
 
 # Using `-gctf` generates full-fledged CTF debug information.
-set opts "additional_flags=-gctf -Wl,--export-dynamic"
+set opts {}
+lappend opts additional_flags=-gctf
+lappend opts ldflags=-Wl,--export-dynamic
+lappend opts ldflags=-Wl,--strip-debug
+lappend opts nowarning
 
 if { [prepare_for_testing "failed to prepare" ${testfile} \
-	  [list $srcfile] [list $opts nowarnings]] } {
+	  [list $srcfile] $opts] } {
     return 0
 }
 

gdb/testsuite/gdb.ctf/multi.exp

@@ -23,10 +23,15 @@ if [skip_ctf_tests] {
 standard_testfile ctf-a.c ctf-b.c ctf-c.c
 
 # Using `-gctf` generates full-fledged CTF debug information.
-set opts "additional_flags=-gctf -Wl,--export-dynamic"
+set opts {}
+lappend opts additional_flags=-gctf
+lappend opts ldflags=-Wl,--export-dynamic
+lappend opts ldflags=-Wl,--strip-debug
+lappend opts nowarning
+
 if { [prepare_for_testing "failed to prepare" ${testfile} \
 	  [list $srcfile $srcfile2 $srcfile3] \
-	  [list $opts nowarnings]] } {
+	  $opts] } {
     return 0
 }