tools build: Add feature test for abi::__cxa_demangle

cxxabi.h is part of libsdtc++ and LLVM's libcxx, providing
abi::__cxa_demangle a portable C++ demangler. Add a feature test to
detect that the function is available.
Signed-off-by: Ian Rogers <irogers@google.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andres Freund <andres@anarazel.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Leo Yan <leo.yan@linaro.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Martin Liška <mliska@suse.cz>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Nathan Chancellor <nathan@kernel.org>
Cc: Nick Desaulniers <ndesaulniers@google.com>
Cc: Pavithra Gurushankar <gpavithrasha@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Quentin Monnet <quentin@isovalent.com>
Cc: Roberto Sassu <roberto.sassu@huawei.com>
Cc: Stephane Eranian <eranian@google.com>
Cc: Tiezhu Yang <yangtiezhu@loongson.cn>
Cc: Tom Rix <trix@redhat.com>
Cc: Yang Jihong <yangjihong1@huawei.com>
Cc: llvm@lists.linux.dev
Link: https://lore.kernel.org/r/20230311065753.3012826-2-irogers@google.comSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/build/Makefile.feature

@@ -80,6 +80,7 @@ FEATURE_TESTS_EXTRA :=                  \
          compile-32                     \
          compile-x32                    \
          cplus-demangle                 \
+         cxa-demangle                   \
          gtk2                           \
          gtk2-infobar                   \
          hello                          \

tools/build/feature/Makefile

@@ -23,6 +23,7 @@ FILES=                                          \
          test-libbfd-liberty.bin                \
          test-libbfd-liberty-z.bin              \
          test-cplus-demangle.bin                \
+         test-cxa-demangle.bin                  \
          test-libcap.bin			\
          test-libelf.bin                        \
          test-libelf-getphdrnum.bin             \
@@ -262,6 +263,9 @@ $(OUTPUT)test-libbfd-liberty-z.bin:
 $(OUTPUT)test-cplus-demangle.bin:
 	$(BUILD) -liberty
 
+$(OUTPUT)test-cxa-demangle.bin:
+	$(BUILDXX)
+
 $(OUTPUT)test-backtrace.bin:
 	$(BUILD)
 

tools/build/feature/test-cxa-demangle.cpp

+// SPDX-License-Identifier: GPL-2.0
+#include <stdio.h>
+#include <stdlib.h>
+#include <cxxabi.h>
+
+int main(void)
+{
+  size_t len = 256;
+  char *output = (char*)malloc(len);
+        int status;
+
+        output = abi::__cxa_demangle("FieldName__9ClassNameFd", output, &len, &status);
+
+        printf("demangled symbol: {%s}\n", output);
+
+        return 0;
+}