waf: build PIEs if supported by the compiler

Currently waf performs a mandatory check for compiler PIE support,
unless --without-pie is specified.
This change makes Waf only perform the mandatory check if --with-pie is
specified. If neither --with-pie nor --without-pie are specified, then
PIEs are only built if compiler support is available.

Signed-off-by: David Disseldorp <ddiss@samba.org>
The last 3 patches address bug #9910 - PIE builds not supported.

Autobuild-User(v4-0-test): Karolin Seeger <kseeger@samba.org>
Autobuild-Date(v4-0-test): Thu May 30 11:37:47 CEST 2013 on sn-devel-104

diff --git a/wscript b/wscript
index 84d56ae84a173a9abbb2410d179d6aee5177f12f..087e950af516e5bcb8d18b1325ae9d1eabf84719 100644 (file)
--- a/wscript
+++ b/wscript
@@ -57,8 +57,9 @@ def set_options(opt):
                    action='store_true', dest='without_ad_dc', default=False)
 
     opt.add_option('--with-pie',
-                  help=("Build Position Independent Executables (default)"),
-                  action="store_true", dest='enable_pie', default=True)
+                  help=("Build Position Independent Executables " +
+                        "(default if supported by compiler)"),
+                  action="store_true", dest='enable_pie')
     opt.add_option('--without-pie',
                   help=("Disable Position Independent Executable builds"),
                   action="store_false", dest='enable_pie')
@@ -175,10 +176,15 @@ def configure(conf):
     
     conf.SAMBA_CONFIG_H('include/config.h')
 
-    if Options.options.enable_pie == True:
-        conf.check_cc(cflags='-fPIE', ldflags='-pie', mandatory=True,
-                      msg="Checking compiler for PIE support")
-        conf.env['ENABLE_PIE'] = True
+    if Options.options.enable_pie != False:
+        if Options.options.enable_pie == True:
+                need_pie = True
+        else:
+                # not specified, only build PIEs if supported by compiler
+                need_pie = False
+        if conf.check_cc(cflags='-fPIE', ldflags='-pie', mandatory=need_pie,
+                         msg="Checking compiler for PIE support"):
+               conf.env['ENABLE_PIE'] = True
 
 def etags(ctx):
     '''build TAGS file using etags'''