[Savannah-hackers-public] [PATCH] configure.ac: add detection of symver gcc attribute

[Giulio Benetti]

From: Thomas Petazzoni <thomas.petazzoni@bootlin.com>

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
Signed-off-by: Giulio Benetti <giulio.benetti@benettiengineering.com>
---
 configure.ac       | 15 +++++++++++++++
 libattr/syscalls.c |  2 +-
 2 files changed, 16 insertions(+), 1 deletion(-)

diff --git a/configure.ac b/configure.ac
index 7e362e9..98477b5 100644
--- a/configure.ac
+++ b/configure.ac
@@ -57,6 +57,21 @@ AS_CASE([$host_os],
        [linux*], [os_linux=yes])
 AM_CONDITIONAL([OS_LINUX], [test "x$os_linux" = "xyes"])
 
+AC_CACHE_CHECK(whether __attribute__((__symver__())) is supported,
+       gcc_cv_symver_attribute,
+       [cat > conftest.c <<EOF
+void foo (void) {}
+__typeof(foo) foo __attribute__ ((__symver__("foo@foo")));
+EOF
+       gcc_cv_symver_attribute=no
+       if ${CC-cc} -Werror -S conftest.c -o conftest.s >/dev/null 2>&1; then \
+           gcc_cv_symver_attribute=yes
+       fi
+       rm -f conftest.[cs]
+])
+AS_IF([test $gcc_cv_symver_attribute = yes],
+      [AC_DEFINE(HAVE_SYMVER_ATTRIBUTE, [], [GCC supports symver attribute])])
+
 AC_CONFIG_COMMANDS([include/attr],
        [dnl
        rm -rf include/attr
diff --git a/libattr/syscalls.c b/libattr/syscalls.c
index 907560a..caa70bc 100644
--- a/libattr/syscalls.c
+++ b/libattr/syscalls.c
@@ -32,7 +32,7 @@
  * fall back to traditional .symver asm directive otherwise.
  */
 #ifdef __has_attribute
-# if __has_attribute(__symver__)
+# if defined(HAVE_SYMVER_ATTRIBUTE)
 #  define SYMVER(cn, vn) __typeof(cn) cn __attribute__((__symver__(vn)))
 # elif __has_attribute(__no_reorder__)
    /*
-- 
2.43.0