1 files changed, 93 insertions, 0 deletions
diff --git a/m4/keywords.m4 b/m4/keywords.m4
new file mode 100644
index 0000000..b4b7e00
--- /dev/null
+++ b/m4/keywords.m4
@@ -0,0 +1,93 @@
+dnl AC_C_RESTRICT
+dnl Do nothing if the compiler accepts the restrict keyword.
+dnl Otherwise define restrict to __restrict__ or __restrict if one of
+dnl those work, otherwise define restrict to be empty.
+AC_DEFUN([AC_C_RESTRICT],
+    [AC_MSG_CHECKING([for restrict])
+    ac_cv_c_restrict=no
+    for ac_kw in restrict __restrict__ __restrict; do
+        AC_TRY_COMPILE([],[char * $ac_kw p;],[ac_cv_c_restrict=$ac_kw; break])
+    done
+    AC_MSG_RESULT([$ac_cv_c_restrict])
+    case $ac_cv_c_restrict in
+        restrict) ;;
+        no)     AC_DEFINE([restrict],,
+                    [Define as `__restrict' if that's what the C compiler calls
+                    it, or to nothing if it is not supported.]) ;;
+        *)      AC_DEFINE_UNQUOTED([restrict],$ac_cv_c_restrict) ;;
+    esac])
+
+dnl AC_C_BUILTIN_EXPECT
+dnl Check whether compiler understands __builtin_expect.
+AC_DEFUN([AC_C_BUILTIN_EXPECT],
+    [AC_CACHE_CHECK([for __builtin_expect],[ac_cv_builtin_expect],
+        [cat > conftest.c <<EOF
+#line __oline__ "configure"
+int foo (int a)
+{
+    a = __builtin_expect (a, 10);
+    return a == 10 ? 0 : 1;
+}
+EOF
+        if AC_TRY_COMMAND([${CC-cc} $CFLAGS -nostdlib -nostartfiles
+            -o conftest conftest.c -lgcc >&AC_FD_CC]); then
+            ac_cv_builtin_expect=yes
+        else
+            ac_cv_builtin_expect=no
+        fi
+        rm -f conftest*])
+    if test x"$ac_cv_builtin_expect" = x"yes"; then
+        AC_DEFINE(HAVE_BUILTIN_EXPECT,,
+            [Define if you have the `__builtin_expect' function.])
+    fi])
+
+dnl AC_C_ALWAYS_INLINE
+dnl Define inline to something appropriate, including the new always_inline
+dnl attribute from gcc 3.1
+AC_DEFUN([AC_C_ALWAYS_INLINE],
+    [AC_C_INLINE
+    if test x"$GCC" = x"yes" -a x"$ac_cv_c_inline" = x"inline"; then
+        AC_MSG_CHECKING([for always_inline])
+        SAVE_CFLAGS="$CFLAGS"
+        CFLAGS="$CFLAGS -Wall -Werror"
+        AC_TRY_COMPILE([],
+            [__attribute__ ((__always_inline__)) void f (void);
+            #ifdef __cplusplus
+            42 = 42;    // obviously illegal - we want c++ to fail here
+            #endif],
+            [ac_cv_always_inline=yes],[ac_cv_always_inline=no])
+        CFLAGS="$SAVE_CFLAGS"
+        AC_MSG_RESULT([$ac_cv_always_inline])
+        if test x"$ac_cv_always_inline" = x"yes"; then
+            AC_DEFINE_UNQUOTED([inline],[__attribute__ ((__always_inline__))])
+        fi
+    fi])
+
+dnl AC_C_ATTRIBUTE_ALIGNED
+dnl define ATTRIBUTE_ALIGNED_MAX to the maximum alignment if this is supported
+AC_DEFUN([AC_C_ATTRIBUTE_ALIGNED],
+    [SAV_CFLAGS=$CFLAGS;
+    if test x"$GCC" = xyes; then CFLAGS="$CFLAGS -Werror"; fi
+    AC_CACHE_CHECK([__attribute__ ((aligned ())) support],
+        [ac_cv_c_attribute_aligned],
+        [ac_cv_c_attribute_aligned=0
+        for ac_cv_c_attr_align_try in 2 4 8 16 32 64; do
+            AC_TRY_COMPILE([],
+                [static struct s {
+                    char a;
+                    char b __attribute__ ((aligned($ac_cv_c_attr_align_try)));
+                } S = {0, 0};
+                switch (1) {
+                    case 0:
+                    case (long)(&((struct s *)0)->b) == $ac_cv_c_attr_align_try:
+                        return 0;
+                }
+                return (long)&S;],
+                [ac_cv_c_attribute_aligned=$ac_cv_c_attr_align_try])
+        done])
+    if test x"$ac_cv_c_attribute_aligned" != x"0"; then
+        AC_DEFINE_UNQUOTED([ATTRIBUTE_ALIGNED_MAX],
+            [$ac_cv_c_attribute_aligned],[maximum supported data alignment])
+    fi
+    CFLAGS=$SAV_CFLAGS])
+