propagate from branch 'net.randombit.botan' (head 39f53266912f33dc48e942b1b865ddcd6af66d8d)

            to branch 'net.randombit.botan.cxx11' (head 0bf26cec09f71e75c547b4ec53365748c6d80d86)

1 files changed, 12 insertions, 9 deletions

diff --git a/configure.py b/configure.py
index bb0dbc192..4d0905340 100755
--- a/configure.py
+++ b/configure.py
@@ -1654,15 +1654,6 @@ def main(argv = None):
 
     (modules, archinfo, ccinfo, osinfo) = load_info_files(options)
 
-    if options.os is None:
-        options.os = platform.system().lower()
-
-        if re.match('^cygwin_.*', options.os):
-            logging.debug("Converting '%s' to 'cygwin'", options.os)
-            options.os = 'cygwin'
-
-        logging.info('Guessing target OS is %s (use --os to set)' % (options.os))
-
     if options.compiler is None:
         if options.os == 'windows':
             if have_program('g++') and not have_program('cl'):
@@ -1674,6 +1665,18 @@ def main(argv = None):
         logging.info('Guessing to use compiler %s (use --cc to set)' % (
             options.compiler))
 
+    if options.os is None:
+        options.os = platform.system().lower()
+
+        if re.match('^cygwin_.*', options.os):
+            logging.debug("Converting '%s' to 'cygwin'", options.os)
+            options.os = 'cygwin'
+
+        if options.os == 'windows' and options.compiler == 'gcc':
+            logging.warning('Detected GCC on Windows; use --os=cygwin or --os=mingw?')
+
+        logging.info('Guessing target OS is %s (use --os to set)' % (options.os))
+
     if options.compiler not in ccinfo:
         raise Exception('Unknown compiler "%s"; available options: %s' % (
             options.compiler, ' '.join(sorted(ccinfo.keys()))))