Fix build for darwin

Fix build for darwin, when ./configured --disable-driglx-direct

- darwin ld doesn't support -Bsymbolic or --version-script, so check if ld
supports those options before using them
- define GLX_ALIAS_UNSUPPORTED as config/darwin used to, as aliasing of non-weak
symbols isn't supported
- default to -with-dri-drivers=swrast

v2:
Use -Wl,-Bsymbolic, as before, not -Bsymbolic
Test that ld --version-script works, rather than just looking for it in ld --help
Don't use -Wl,--no-undefined on darwin, either

Signed-off-by: Jon TURNEY <jon.turney@dronecode.org.uk>
Reviewed-by: Jeremy Huddleston Sequoia <jeremyhu@apple.com>
Reviewed-by: Emil Velikov <emil.l.velikov@gmail.com>
diff --git a/configure.ac b/configure.ac
index 76d1333..675a4a6 100644
--- a/configure.ac
+++ b/configure.ac
@@ -316,6 +316,22 @@
 fi
 
 dnl
+dnl Check if linker supports -Bsymbolic
+dnl
+save_LDFLAGS=$LDFLAGS
+LDFLAGS="$LDFLAGS -Wl,-Bsymbolic"
+AC_MSG_CHECKING([if ld supports -Bsymbolic])
+AC_LINK_IFELSE(
+    [AC_LANG_SOURCE([int main() { return 0;}])],
+    [AC_MSG_RESULT([yes])
+        BSYMBOLIC="-Wl,-Bsymbolic";],
+    [AC_MSG_RESULT([no])
+        BSYMBOLIC="";])
+LDFLAGS=$save_LDFLAGS
+
+AC_SUBST([BSYMBOLIC])
+
+dnl
 dnl Check if linker supports garbage collection
 dnl
 save_LDFLAGS=$LDFLAGS
@@ -345,6 +361,28 @@
 AC_SUBST([LD_NO_UNDEFINED])
 
 dnl
+dnl Check if linker supports version scripts
+dnl
+AC_MSG_CHECKING([if the linker supports version-scripts])
+save_LDFLAGS=$LDFLAGS
+LDFLAGS="$LDFLAGS -Wl,--version-script=conftest.map"
+cat > conftest.map <<EOF
+VERSION_1 {
+     global:
+         main;
+
+     local:
+         *;
+};
+EOF
+AC_LINK_IFELSE(
+    [AC_LANG_SOURCE([int main() { return 0;}])],
+    [have_ld_version_script=yes;AC_MSG_RESULT(yes)],
+    [have_ld_version_script=no; AC_MSG_RESULT(no)])
+LDFLAGS=$save_LDFLAGS
+AM_CONDITIONAL(HAVE_LD_VERSION_SCRIPT, test "$have_ld_version_script" = "yes")
+
+dnl
 dnl compatibility symlinks
 dnl
 case "$host_os" in
@@ -1043,6 +1081,12 @@
             with_dri_drivers="swrast"
         fi
         ;;
+    darwin*)
+        DEFINES="$DEFINES -DUSE_EXTERNAL_DXTN_LIB=1 -DGLX_ALIAS_UNSUPPORTED"
+        if test "x$with_dri_drivers" = "xyes"; then
+            with_dri_drivers="swrast"
+        fi
+        ;;
     esac
 
     # default drivers