fail immediately in the build script if the Qt source is not available

fixes #2673

CHANGELOG.md

@@ -3,6 +3,7 @@ v0.12.4 (unreleased)
 * update OpenSSL to 1.0.2g
 * **[qt]** change screen size in headless mode to a more sane value (1366x768)
 * **#2416**: make background transparent by default for headers/footers
+* **#2673**: fail immediately in the build script if the Qt source is not available
 * **#2885**: enforce UTF-8 encoding for input strings in the API
 * **#2887**: improve docs to make examples of header/footer variables more explicit
 

scripts/build.py

@@ -1225,6 +1225,10 @@ def usage(exit_code=2):
 def main():
     rootdir = os.path.realpath(os.path.join(os.path.dirname(os.path.realpath(__file__)), '..'))
     basedir = os.path.join(rootdir, 'static-build')
+
+    if not exists(os.path.join(rootdir, 'qt', 'configure')):
+        error('error: source code for Qt not available, cannot proceed.')
+
     if len(sys.argv) == 1:
         usage(0)