1 files changed, 69 insertions, 0 deletions
diff --git a/config/no-executables.m4 b/config/no-executables.m4
new file mode 100644
index 000000000..90616245e
--- /dev/null
+++ b/config/no-executables.m4
@@ -0,0 +1,69 @@
+# GCC_NO_EXECUTABLES
+# -----------------
+# FIXME: The GCC team has specific needs which the current Autoconf
+# framework cannot solve elegantly.  This macro implements a dirty
+# hack until Autoconf is able to provide the services its users
+# need.
+#
+# Several of the support libraries that are often built with GCC can't
+# assume the tool-chain is already capable of linking a program: the
+# compiler often expects to be able to link with some of such
+# libraries.
+#
+# In several of these libraries, workarounds have been introduced to
+# avoid the AC_PROG_CC_WORKS test, that would just abort their
+# configuration.  The introduction of AC_EXEEXT, enabled either by
+# libtool or by CVS autoconf, have just made matters worse.
+#
+# Unlike the previous AC_NO_EXECUTABLES, this test does not
+# disable link tests at autoconf time, but at configure time.
+# This allows AC_NO_EXECUTABLES to be invoked conditionally.
+AC_DEFUN_ONCE([GCC_NO_EXECUTABLES],
+[m4_divert_push([KILL])
+
+AC_BEFORE([$0], [_AC_COMPILER_EXEEXT])
+AC_BEFORE([$0], [AC_LINK_IFELSE])
+
+m4_define([_AC_COMPILER_EXEEXT],
+[AC_LANG_CONFTEST([AC_LANG_PROGRAM()])
+# FIXME: Cleanup?
+AS_IF([AC_TRY_EVAL(ac_link)], [gcc_no_link=no], [gcc_no_link=yes])
+if test x$gcc_no_link = xyes; then
+  # Setting cross_compile will disable run tests; it will
+  # also disable AC_CHECK_FILE but that's generally
+  # correct if we can't link.
+  cross_compiling=yes
+  EXEEXT=
+else
+  ]m4_defn([_AC_COMPILER_EXEEXT])dnl
+fi
+)
+
+m4_define([AC_LINK_IFELSE],
+if test x$gcc_no_link = xyes; then
+  AC_MSG_ERROR([Link tests are not allowed after [[$0]].])
+fi
+m4_defn([AC_LINK_IFELSE]))
+
+dnl This is a shame.  We have to provide a default for some link tests,
+dnl similar to the default for run tests.
+m4_define([AC_FUNC_MMAP],
+if test x$gcc_no_link = xyes; then
+  if test "x${ac_cv_func_mmap_fixed_mapped+set}" != xset; then
+    ac_cv_func_mmap_fixed_mapped=no
+  fi
+fi
+if test "x${ac_cv_func_mmap_fixed_mapped}" != xno; then
+  m4_defn([AC_FUNC_MMAP])
+fi)
+
+m4_divert_pop()dnl
+])# GCC_NO_EXECUTABLES
+
+# Use the strongest available test out of AC_TRY_COMPILE and AC_TRY_LINK.
+AC_DEFUN([GCC_TRY_COMPILE_OR_LINK],
+[if test x$gcc_no_link = xyes; then
+  AC_TRY_COMPILE([$1], [$2], [$3], [$4])
+else
+  AC_TRY_LINK([$1], [$2], [$3], [$4])
+fi])