Warn the user if targetting for GCC on Windows without an explicit

--os=windows since likely they actually wanted either --os=cygwin
or --os=mingw

2 files changed, 17 insertions, 9 deletions

diff --git a/configure.py b/configure.py
index 6fdaf16e7..876108a9f 100755
--- a/configure.py
+++ b/configure.py
@@ -1686,15 +1686,6 @@ 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'):
@@ -1706,6 +1697,18 @@ 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()))))
diff --git a/doc/log.txt b/doc/log.txt
index acce16410..9edd60018 100644
--- a/doc/log.txt
+++ b/doc/log.txt
@@ -23,6 +23,11 @@ Version 1.10.2, Not Yet Released
 
 * Add AltiVec detection for OpenBSD, contributed by Brad Smith (PR 162)
 
+* If targetting GCC on a Windows system, configure.py will warn that
+  likely you wanted to configure for either MinGW or Cygwin, not the
+  generic Windows target which is oriented to Win32 plus the Visual
+  C++ runtime.
+
 * Fixed a compilation problem of the dynamic loader hooks under MinGW GCC
 
 * Don't set a soname on OpenBSD, as it doesn't support it (PR 158)