scons: Increase the minimum clang version to 3.9.

This matches what's documented elsewhere. We *need* version 3.4 to
support c++14, but we support only as far back as 3.9. Also, the
argument to set c++14 as the standard is different in 3.4 and earlier
(-std=c++1y), so it makes life slightly easier to move past it to 3.9.

Change-Id: I66fa578dd3222c62907496a888f8068ed0918c7b
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/34819
Reviewed-by: Jason Lowe-Power <power.jg@gmail.com>
Maintainer: Jason Lowe-Power <power.jg@gmail.com>
Tested-by: kokoro <noreply+kokoro@google.com>

diff --git a/SConstruct b/SConstruct
index ca3f1a1dbe04753b4448652c574e55dd7ba56037..0e49df4fc0a6222e5e54072062a507b47a57149c 100755 (executable)
--- a/SConstruct
+++ b/SConstruct
@@ -417,8 +417,8 @@ elif main['CLANG']:
     clang_version_match = clang_version_re.search(CXX_version)
     if (clang_version_match):
         clang_version = clang_version_match.groups()[0]
-        if compareVersions(clang_version, "3.1") < 0:
-            error('clang version 3.1 or newer required.\n'
+        if compareVersions(clang_version, "3.9") < 0:
+            error('clang version 3.9 or newer required.\n'
                   'Installed version:', clang_version)
     else:
         error('Unable to determine clang version.')