diff --git a/NEWS.md b/NEWS.md
index da9eb98..6bdd438 100644
--- a/NEWS.md
+++ b/NEWS.md
@@ -1,5 +1,7 @@
 # watcher (development version)
 
+* Fixes installation failing on systems with a partial or broken system 'libfswatch', now falling back to the bundled build.
+
 # watcher 0.2.0
 
 * Building the bundled 'libfswatch' from source no longer requires 'cmake', now directly using the R C/C++ toolchain.
diff --git a/configure b/configure
index 1a8a350..356f9f3 100755
--- a/configure
+++ b/configure
@@ -66,12 +66,13 @@ else
   FSWATCH_CFLAGS="$LIB_CFLAGS"
   FSWATCH_LIBS="$LIB_LIBS"
 
+  # The probe must LINK, not just compile: a header-only check passes on a
+  # broken partial install (headers present, library missing) and the real
+  # link of watcher.so then fails with 'cannot find -lfswatch'.
   echo "#include <libfswatch/c/libfswatch.h>
-int main() {
-#if FSW_OK
-    *(void *) 0 = 0;
-#endif
-}" | ${CC} ${FSWATCH_CFLAGS} -xc - -o /dev/null > /dev/null 2>&1
+int main(void) {
+    return fsw_init_library();
+}" | ${CC} ${CFLAGS} ${CPPFLAGS} ${FSWATCH_CFLAGS} -xc - -o /dev/null ${LDFLAGS} ${FSWATCH_LIBS} > /dev/null 2>&1
   if [ $? -ne 0 ]; then
     compile_fswatch=1
   else