configure.ac: Check for some brain damage from Clang's assembler.

It doesn't understand `.arch' or the `adcd' instruction.  I'm damned if
I'm writing `dword ptr' everywhere, so Clang users will have to figure
out some way to use Gas if they want the assembler code.

diff --git a/configure.ac b/configure.ac
index 8c32c92ad8ff85cf8842a585594590283b06588c..bdc94be7ee6841e30257ac21ba183962ea414d23 100644 (file)
--- a/configure.ac
+++ b/configure.ac
@@ -98,8 +98,8 @@ case $host_cpu,$host_os in
   *) CPUFAM=nil ABI=nil ;;
 esac
 
-dnl Now check the assembler.  We may have target-specific requirements here,
-dnl so we couldn't do this any earlier.
+dnl Now check the assembler.  We have target-specific requirements here, so
+dnl we couldn't do this any earlier.
 AC_CACHE_CHECK(
   [whether the assembler is likely to work], [mdw_cv_gnuish_as],
   [AC_LANG_PUSH([CPPAS])
@@ -113,6 +113,22 @@ AC_CACHE_CHECK(
        .extern bar
        mymac]])],
      [mdw_cv_gnuish_as=yes], [mdw_cv_gnuish_as=no])
+   case $CPUFAM in
+     x86 | amd64)
+       AC_COMPILE_IFELSE([AC_LANG_SOURCE([[
+       .text
+       .arch pentium4
+       .intel_syntax noprefix
+       .globl  foo
+foo:
+       adcd    var, 0
+       ret
+       .data
+var:   .long   1
+       ]])],
+        [:], [mdw_cv_gnuish_as=no])
+       ;;
+   esac
    AC_LANG_POP([CPPAS])])
 AM_CONDITIONAL([GNUISH_AS], [test $mdw_cv_gnuish_as = yes])
 if test $mdw_cv_gnuish_as = no; then CPUFAM=nil ABI=nil; fi