Fixes: qworkbench.pri: make the gnu linker bail out on non-selfcontained libraries.

src/qworkbench.pri

@@ -54,3 +54,9 @@ unix {
     RCC_DIR = $${OUT_PWD}/.rcc/
     UI_DIR = $${OUT_PWD}/.uic/
 }
+
+linux-g++-* {
+    # Bail out on non-selfcontained libraries. Just a security measure
+    # to prevent checking in code that does not compile on other platforms.
+    QMAKE_LFLAGS += -Wl,--allow-shlib-undefined -Wl,--no-undefined
+}